A chemical substance which cures the disease , is safe to use, has negligible toxicity and does not cause addiction is called a _______ while a chemical substance which cures the disease but is habit forming , causes addiction and has serious side effects is called a _______

Answer

To answer the question, we need to identify two types of chemical substances based on their effects and characteristics:

1. **First Blank**: We are looking for a term that describes a chemical substance that cures diseases, is safe to use, has negligible toxicity, and does not cause addiction. The correct term for this is **non-narcotic drug**.

2. **Second Blank**: The second part of the question asks for a term that describes a chemical substance that cures diseases but is habit-forming, causes addiction, and has serious side effects. The appropriate term for this is **narcotic drug**.

### Final Answer:
A chemical substance which cures the disease, is safe to use, has negligible toxicity and does not cause addiction is called a **non-narcotic drug** while a chemical substance which cures the disease but is habit forming, causes addiction and has serious side effects is called a **narcotic drug**.