The use of insufficient amount of active ingredients prevents the medicine from being effective. Counterfeit medicine is responsible for increasing drug resistance among very dangerous infectious diseases such as: malaria, HIV/AIDS and tuberculosis (TB) because these medications contain incorrect active ingredients which causes some strains of bacteria and viruses to mutate, multiply and spread which results in serious illness and death as a result of improper treatment The use of counterfeit drugs could cause adverse effects, especially if they contain toxic materials, or pathogenic contaminants. Pathogens have been found in case of counterfeited drugs where gentamicin eye drops was contaminated with gentamicin-resistant pseudomonas aeruginosa which led to severe eye infections.