diff --git a/pharmacy.js b/pharmacy.js
index cda44c41..3572479d 100644
--- a/pharmacy.js
+++ b/pharmacy.js
@@ -1,9 +1,140 @@
-export class Drug {
+const DrugName = {
+  HerbalTea: "Herbal Tea",
+  MagicPill: "Magic Pill",
+  Fervex: "Fervex",
+  Dafalgan: "Dafalgan",
+};
+
+const maxBenefit = 50;
+const minBenefit = 0;
+
+export class GenericDrug {
   constructor(name, expiresIn, benefit) {
     this.name = name;
     this.expiresIn = expiresIn;
     this.benefit = benefit;
   }
+
+  get isExpired() {
+    return this.expiresIn <= 0;
+  }
+
+  get canUpdateBenefit() {
+    return this.benefit < maxBenefit && this.benefit > minBenefit;
+  }
+  get canUpdateExpiresIn() {
+    return true;
+  }
+  get benefitVariation() {
+    return this.isExpired ? -2 : -1;
+  }
+
+  updateBenefit() {
+    if (!this.canUpdateBenefit) {
+      return;
+    }
+
+    this.benefit += this.benefitVariation;
+  }
+
+  verifyBenefit() {
+    if (this.benefit > maxBenefit) this.benefit = maxBenefit;
+
+    if (this.benefit < minBenefit) this.benefit = minBenefit;
+  }
+
+  updateExpiresIn() {
+    if (!this.canUpdateExpiresIn) {
+      return;
+    }
+
+    this.expiresIn--;
+  }
+
+  updateBenefitValue() {
+    this.updateBenefit();
+    this.updateExpiresIn();
+    this.verifyBenefit();
+  }
+}
+class HerbalTea extends GenericDrug {
+  constructor(name, expiresIn, benefit) {
+    super(DrugName.HerbalTea, expiresIn, benefit);
+  }
+
+  get benefitVariation() {
+    return this.isExpired ? 2 : 1;
+  }
+}
+
+class MagicPill extends GenericDrug {
+  constructor(name, expiresIn, benefit) {
+    super(DrugName.MagicPill, expiresIn, benefit);
+  }
+
+  get canUpdateBenefit() {
+    return false;
+  }
+  get canUpdateExpiresIn() {
+    return false;
+  }
+}
+
+class Fervex extends GenericDrug {
+  constructor(name, expiresIn, benefit) {
+    super(DrugName.Fervex, expiresIn, benefit);
+  }
+
+  get isExpired() {
+    return this.expiresIn < 0;
+  }
+
+  get benefitVariation() {
+    if (this.expiresIn <= 5) {
+      return 3;
+    } else if (this.expiresIn <= 10) {
+      return 2;
+    }
+
+    return 1;
+  }
+
+  updateBenefitValue() {
+    super.updateBenefitValue();
+
+    if (this.isExpired) {
+      this.benefit = 0;
+    }
+  }
+}
+
+class Dafalgan extends GenericDrug {
+  constructor(name, expiresIn, benefit) {
+    super(DrugName.Dafalgan, expiresIn, benefit);
+  }
+
+  get benefitVariation() {
+    console.log(super.benefitVariation);
+    console.log(super.benefitVariation * 2);
+    return super.benefitVariation * 2;
+  }
+}
+
+export class Drug {
+  constructor(name, expiresIn, benefit) {
+    switch (name) {
+      case DrugName.HerbalTea:
+        return new HerbalTea(name, expiresIn, benefit);
+      case DrugName.MagicPill:
+        return new MagicPill(name, expiresIn, benefit);
+      case DrugName.Fervex:
+        return new Fervex(name, expiresIn, benefit);
+      case DrugName.Dafalgan:
+        return new Dafalgan(name, expiresIn, benefit);
+      default:
+        return new GenericDrug(name, expiresIn, benefit);
+    }
+  }
 }
 
 export class Pharmacy {
@@ -11,54 +142,8 @@ export class Pharmacy {
     this.drugs = drugs;
   }
   updateBenefitValue() {
-    for (var i = 0; i < this.drugs.length; i++) {
-      if (
-        this.drugs[i].name != "Herbal Tea" &&
-        this.drugs[i].name != "Fervex"
-      ) {
-        if (this.drugs[i].benefit > 0) {
-          if (this.drugs[i].name != "Magic Pill") {
-            this.drugs[i].benefit = this.drugs[i].benefit - 1;
-          }
-        }
-      } else {
-        if (this.drugs[i].benefit < 50) {
-          this.drugs[i].benefit = this.drugs[i].benefit + 1;
-          if (this.drugs[i].name == "Fervex") {
-            if (this.drugs[i].expiresIn < 11) {
-              if (this.drugs[i].benefit < 50) {
-                this.drugs[i].benefit = this.drugs[i].benefit + 1;
-              }
-            }
-            if (this.drugs[i].expiresIn < 6) {
-              if (this.drugs[i].benefit < 50) {
-                this.drugs[i].benefit = this.drugs[i].benefit + 1;
-              }
-            }
-          }
-        }
-      }
-      if (this.drugs[i].name != "Magic Pill") {
-        this.drugs[i].expiresIn = this.drugs[i].expiresIn - 1;
-      }
-      if (this.drugs[i].expiresIn < 0) {
-        if (this.drugs[i].name != "Herbal Tea") {
-          if (this.drugs[i].name != "Fervex") {
-            if (this.drugs[i].benefit > 0) {
-              if (this.drugs[i].name != "Magic Pill") {
-                this.drugs[i].benefit = this.drugs[i].benefit - 1;
-              }
-            }
-          } else {
-            this.drugs[i].benefit =
-              this.drugs[i].benefit - this.drugs[i].benefit;
-          }
-        } else {
-          if (this.drugs[i].benefit < 50) {
-            this.drugs[i].benefit = this.drugs[i].benefit + 1;
-          }
-        }
-      }
+    for (const drug of this.drugs) {
+      drug.updateBenefitValue();
     }
 
     return this.drugs;
diff --git a/pharmacy.test.js b/pharmacy.test.js
index f0925fc1..31e7564b 100644
--- a/pharmacy.test.js
+++ b/pharmacy.test.js
@@ -1,9 +1,165 @@
 import { Drug, Pharmacy } from "./pharmacy";
 
 describe("Pharmacy", () => {
-  it("should decrease the benefit and expiresIn", () => {
-    expect(new Pharmacy([new Drug("test", 2, 3)]).updateBenefitValue()).toEqual(
-      [new Drug("test", 1, 2)]
-    );
+  describe("Regular Drug", () => {
+    describe("When regular drug is not expired and benefit not null", () => {
+      it("should decrease the benefit and expiresIn by one", () => {
+        expect(
+          new Pharmacy([new Drug("Doliprane", 2, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Doliprane", 1, 2)]);
+      });
+    });
+
+    describe("When regular drug has benefit to 0", () => {
+      it("should decrease expiresIn by one and not benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Doliprane", 2, 0)]).updateBenefitValue()
+        ).toEqual([new Drug("Doliprane", 1, 0)]);
+      });
+    });
+
+    describe("When regular drug is expired", () => {
+      it("Should decrease expiresIn by one and benefit by two", () => {
+        expect(
+          new Pharmacy([new Drug("Doliprane", -2, 30)]).updateBenefitValue()
+        ).toEqual([new Drug("Doliprane", -3, 28)]);
+      });
+    });
+  });
+
+  describe("Magic Pill", () => {
+    describe("When Magic Pill has valid values", () => {
+      it("Should not decrease the benefit nor expiresIn", () => {
+        expect(
+          new Pharmacy([new Drug("Magic Pill", 2, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Magic Pill", 2, 3)]);
+      });
+    });
+    describe("When Magic Pill has benefit > 50", () => {
+      it("Should not decrease expiresIn ans put the benefiit to 50", () => {
+        expect(
+          new Pharmacy([new Drug("Magic Pill", 2, 60)]).updateBenefitValue()
+        ).toEqual([new Drug("Magic Pill", 2, 50)]);
+      });
+    });
+  });
+
+  describe("Dafalgan", () => {
+    describe("When Dafalgan is not expired", () => {
+      it("Should decrease the benefit by 2 and decrease expiresIn by one", () => {
+        expect(
+          new Pharmacy([new Drug("Dafalgan", 2, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Dafalgan", 1, 1)]);
+      });
+    });
+
+    describe("When the Dafalgan is expired", () => {
+      it("Should decrease the benefit by 4 and decrease expiresIn by one", () => {
+        expect(
+          new Pharmacy([new Drug("Dafalgan", -2, 5)]).updateBenefitValue()
+        ).toEqual([new Drug("Dafalgan", -3, 1)]);
+      });
+    });
+  });
+
+  describe("Herbal Tea", () => {
+    describe("When Herbal Tea is not expired", () => {
+      it("should decrease expiresIn and increase benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Herbal Tea", 2, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Herbal Tea", 1, 4)]);
+      });
+    });
+
+    describe("When Herbal Tea is expired", () => {
+      it("Should decrease expiresIn and increase benefit by 2)", () => {
+        expect(
+          new Pharmacy([new Drug("Herbal Tea", -1, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Herbal Tea", -2, 5)]);
+      });
+    });
+    describe("When Herbal Tea is expired and benfit is at max (50)", () => {
+      it("Should decrease expiresIn and maintain benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Herbal Tea", -1, 50)]).updateBenefitValue()
+        ).toEqual([new Drug("Herbal Tea", -2, 50)]);
+      });
+    });
+    describe("When Herbal Tea is expired and benfit is at 49", () => {
+      it("Should decrease expiresIn and increase benefit to 1 (to max)", () => {
+        expect(
+          new Pharmacy([new Drug("Herbal Tea", -1, 49)]).updateBenefitValue()
+        ).toEqual([new Drug("Herbal Tea", -2, 50)]);
+      });
+    });
+  });
+
+  describe("Fervex", () => {
+    describe("When Fervex is not expired", () => {
+      it("Should decrease expiresIn and increase benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 20, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 19, 4)]);
+      });
+    });
+
+    describe("When Fervex is below 10 days expiresIn", () => {
+      it("Should decrease expiresIn by one and increase benefit by 2", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 10, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 9, 5)]);
+      });
+    });
+
+    describe("When Fervex is below 5 days expiresIn", () => {
+      it("Should decrease expiresIn by one and increase benefit by 3", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 5, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 4, 6)]);
+      });
+    });
+
+    describe("When Fervex is below 0 days expiresIn", () => {
+      it("Should decrease expiresIn by one and set benefit to 0", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", -1, 3)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", -2, 0)]);
+      });
+    });
+    describe("When Fervex is below 0 days expiresIn and benefit at max (50)", () => {
+      it("Should decrease expiresIn and maintain benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 20, 50)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 19, 50)]);
+      });
+    });
+    describe("When Fervex is below 10 days expiresIn and benefit at max (50) ", () => {
+      it("Should decrease expiresIn and maintain benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 10, 50)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 9, 50)]);
+      });
+    });
+    describe("When Fervex is below 5 days expiresIn and benefit at max (50)", () => {
+      it("Should decrease expiresIn and maintain benefit", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 5, 50)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 4, 50)]);
+      });
+    });
+    describe("When Fervex is below 10 days expiresIn and benefit is 49", () => {
+      it("should decrease expiresIn and increase benefit by 1 (to max)", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 10, 49)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 9, 50)]);
+      });
+    });
+    describe("When Fervex is below 5 days expiresIn and benefit is 58", () => {
+      it("should decrease expiresIn and increase benefit by 2 (to max)", () => {
+        expect(
+          new Pharmacy([new Drug("Fervex", 5, 48)]).updateBenefitValue()
+        ).toEqual([new Drug("Fervex", 4, 50)]);
+      });
+    });
   });
 });