Benzoyl-Peroxide (or simply BPO) is a medication used to treat mild to moderate acne. It is actually effective for reducing the number and severity of acne lesions. Plus, it has a bactericidal effect on the bacteria associated with acne, and does not induce antibiotic resistance. However, combination products such as benzoyl peroxide/clindamycin and benzoyl peroxide/salicylic acid appear to be slightly more effective than benzoyl peroxide alone for the treatment of acne lesions. This acne treatment is typically applied to the affected areas in gel, cream, or liquid. As for its side effects, Benzoyl peroxide commonly causes initial dryness and sometimes irritation, although the skin develops tolerance after a week or so. There are, however, a small percentage of people who are much more sensitive to it and liable to suffer burning, itching, crusting, and possibly swelling. Therefore, the safest thing to do is apply the lowest concentration, and once tolerance is achieved, increasing the quantity or concentration may give better subsequent acne clearance. In addition, irritation can be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure. It is worth noting that Benzoyl peroxide is likely safe to use while you're pregnant. This is because your body absorbs very little of the drug. Besides, no problems with use during pregnancy have been reported. You should nonetheless talk to your doctor before using benzoyl peroxide or any drug while pregnant.