Question

are all drugs capable of causing side effects?
no, all drugs are designed to not have side effects.
side effects are only caused by drugs classified as allergens.
yes, all drugs have inherent side effects.

Explanation:

All drugs interact with the body's systems. Even when designed for a specific therapeutic effect, they can affect other physiological processes. This is due to the complexity of human biology and the way drugs are metabolized and distributed. For example, a pain - relieving drug might also affect the digestive system.

Answer:

Yes, all drugs have inherent side effects.