You should not use this medication if you are on a special diet low in galactose (milk sugar).

Before taking lactulose, tell your doctor if you have diabetes or if you need to have any type of intestinal test using a scope (such as a colonoscopy).

Stop using lactulose and call your doctor at once if you have severe or ongoing diarrhea.

The liquid form of lactulose may become slightly darken in color, but this is a harmless effect. However, do not use the medicine if it becomes very dark, or if it gets thicker or thinner in texture.

If you use lactulose over a long period of time, your doctor may want you to have occasional blood tests. Do not miss any scheduled appointments.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. It is not known whether lactulose passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Avoid using antacids without your doctor's advice. Use only the specific type of antacid your doctor recommends. Antacids contain different medicines and some types can make it harder for your body to absorb lactulose.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using lactulose and call your doctor at once if you have severe or ongoing diarrhea.

Less serious side effects may include: bloating, gas; stomach pain; diarrhea; or nausea, vomiting.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.