The most common side-effects of taking laxatives are bloating, abdominal cramps, malaise, and dehydration. These effects are mostly mild, and they disappear after we stop taking laxatives. In rare cases, or in case of improper or excessive consumption of laxatives, side-effects such as rectal bleeding, cramps, difficulty in swallowing, rash or irregular heart rhythm may occur. If you notice any of these side-effects, immediately stop taking the laxative and ask for medical help.