Medicines are

Options

A. drugs which produce harmful effect
B. drugs which produce therapeutic and useful effect
C. drugs which have no use
D. all of these

Answer

To solve the question "Medicines are," we will analyze the options provided and determine which one correctly defines what medicines are.

### Step-by-Step Solution:

1. **Understanding the Definition of Medicines:**
- Medicines are substances that are used to diagnose, cure, treat, or prevent diseases. They are often referred to as drugs.
- They interact with biological systems, particularly macromolecular targets (like proteins, enzymes, or receptors), to produce a biological response.

2. **Analyzing the Options:**
- **Option 1:** "Drugs which produce harmful effects."
- This option is incorrect because while some drugs can have harmful effects, medicines are specifically intended to provide therapeutic benefits.

- **Option 2:** "Drugs which produce therapeutic and useful effects."
- This option is correct. Medicines are designed to have beneficial effects on health and are used to treat or prevent illnesses.

- **Option 3:** "Drugs which have no use."
- This option is incorrect as it contradicts the very purpose of medicines, which is to be useful in treating health conditions.

- **Option 4:** "All of these."
- This option is incorrect because not all the previous statements are true. Only Option 2 accurately describes medicines.

3. **Conclusion:**
- Based on the analysis, the correct answer is **Option 2: Drugs which produce therapeutic and useful effects.**