Blood in humans is buffered to maintain a pH of 7.40. Some household cleaners that are meant for tough jobs have extreme pH levels. Extreme caution must be taken with these substances. Acids work well for dissolving stains and mineral scale. Bases work well for dissolving fats and oils.
Some cleaners contain other ingredients to produce gases and heat to be more effective.
The human stomach secretes hydrochloric acid to kill microorganisms and aid in digestion. Most often contain magnesium or aluminum hydroxide and bicarbonate or carbonate salts. In small doses it works as an antacid. In larger doses it works as a laxative. Some newer medications like Tagamet and Pepcid are drugs which prevent the secretion of acid.