Which statement best distinguishes antiseptics from disinfectants?

• A. Antiseptics work on living tissue to reduce microbes; disinfectants work on inanimate surfaces to kill microbes.
• B. Antiseptics kill all microbes instantly; disinfectants kill most microbes over time.
• C. Antiseptics are used on surfaces; disinfectants are used on skin.
• D. Antiseptics require heat; disinfectants work at room temperature

Answer: (A)

Antiseptics and disinfectants are distinguished by where they’re used and what they’re meant to do. Antiseptics are formulated for use on living tissue, like skin or mucous membranes, to reduce or inhibit microorganisms and help prevent infection. Disinfectants are designed for non-living surfaces and objects, with the goal of killing or inactivating microorganisms on those surfaces. That living-vs-nonliving context is what sets them apart and explains why the statement is correct.

The other ideas don’t fit as well. Antiseptics don’t guarantee instant, complete elimination of all microbes on living tissue, and disinfectants don’t universally act by killing most microbes only over time; both rely on specific contact times and conditions. Also, the common sense distinction is not about surfaces vs skin in opposite directions, nor about needing heat—both types can be used at typical room temperatures, depending on the product and protocol.