When two or more medications are consumed, there is a potential that they will interact with one another. The effectiveness or negative effects of the medications may be increased or decreased as a result of the interaction. As a person takes more drugs, the probability of drug interactions increases. As a result, those who take multiple medications are most likely to suffer from interactions. Because medical treatment is needed to treat problems brought on by side effects or changes in effectiveness, drug interactions raise the cost of healthcare. Interactions can also cause psychological distress, which might be avoided.