Nausea
Some people have reported feeling nauseous after drinking alkaline water, but it is not clear why this happens. It is possible that the body is not used to the high pH of alkaline water and this causes some discomfort. If you experience nausea after drinking alkaline water, try reducing the amount you drink or diluting it with regular water.
Constipation
While constipation is not a common side effect, it can occur in some individuals. If you experience constipation after drinking alkaline water, it is important to increase your intake of fluids and fiber. You may also want to consider taking a stool softener or laxative.