Antihistamine pills are to nullify:

Options

A. malaria
B. Typhoid
C. allergic reaction
D. autoimmune diseases

Answer

**Step-by-Step Solution:**

1. **Understanding Antihistamines**: Antihistamines are medications designed to counteract the effects of histamines in the body. Histamines are chemicals released during allergic reactions.

2. **Identifying the Context**: The question asks what antihistamine pills are meant to nullify. We need to determine which of the provided options is related to histamine release.

3. **Analyzing the Options**:
- **Option 1: Malaria** - Antihistamines are not used for malaria, which is a parasitic infection.
- **Option 2: Typhoid** - Similarly, antihistamines are not relevant for typhoid fever, a bacterial infection.
- **Option 3: Allergic Reaction** - This is a condition where histamines are released in response to allergens, making this a potential correct answer.
- **Option 4: Autoimmune Diseases** - Antihistamines do not target autoimmune diseases, which involve the immune system attacking the body’s own cells.

4. **Confirming the Correct Answer**: Since antihistamines are specifically used to alleviate symptoms caused by allergic reactions (due to histamine release), we can conclude that the correct answer is **Option 3: Allergic Reaction**.

5. **Mechanism of Action**: Antihistamines work by blocking histamine receptors, thereby preventing histamines from triggering allergic symptoms. This helps to nullify the effects of the allergic reaction.

6. **Conclusion**: Based on the analysis, antihistamine pills are specifically designed to nullify allergic reactions.

**Final Answer**: Antihistamine pills are to nullify **allergic reactions** (Option 3).

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