Here’s a quick glimpse at their incredible health benefits. The phytochemicals in onions along with their vitamin C help improve immunity. Onions contain chromium, which assists in regulating blood sugar. … A powerful compound called quercetin in onions is known to play a significant role in preventing cancer.
Onions are slightly acidic, which could have antibacterial effects if you rubbed the juice on things, but these are much less effective than bleach or chemical antibiotics.