What is chemotherapy primarily used for?

Chemotherapy is primarily used for treating cancer because it involves the use of powerful drugs that target rapidly dividing cells, a characteristic of cancerous cells. The treatment aims to eliminate cancer cells, shrink tumors, and prevent the spread of cancer throughout the body. Chemotherapy can also be used as a complementary treatment to surgery or radiation therapy, helping to eradicate any remaining cancer cells after these treatments.

The other options do not align with the primary purpose of chemotherapy. Treating infections typically involves antibiotics, which target bacteria rather than cancer cells. High blood pressure is managed with antihypertensive medications, which work to lower blood pressure but are not effective against cancer. Allergies are commonly treated with antihistamines or corticosteroids, which alleviate allergic reactions rather than targeting cancerous growths. Thus, chemotherapy's specific role in cancer treatment distinguishes it from these other medical concerns.