As bulk-forming laxatives are not absorbed, they have no systemic effects. Also, they do not interact with other medicines and do not appear to interfere significantly with drug absorption. However, there is a risk of oesophageal and intestinal obstruction if preparations are not taken with plenty of water. It is therefore important to stress the importance of carefully following instructions for administration.

Abdominal distension and flatulence are possible side effects, and for this reason bulk-forming laxatives may cause discomfort if taken in the later stages of pregnancy. They are not contraindicated in pregnancy, although the general precautions that apply to use of any medicine in this situation should be observed.

Some bulk-forming laxative preparations contain glucose, which should be taken into account when making recommendations for patients with diabetes.

Bulk laxatives may not be suitable for patients who need to severely restrict their fluid intake.