Lactulose Oral Syrup is a laxative medicine used to treat constipation and hepatic encephalopathy (a liver-related condition that affects brain function). It works by drawing water into the bowel, softening the stool, and making bowel movements easier. In patients with liver disease, it helps reduce the absorption of ammonia from the intestine. 

Common side effects include bloating, gas, stomach discomfort, nausea, and diarrhea. Rare but serious side effects may include severe dehydration, electrolyte imbalance, and severe diarrhea. Overall, Lactulose Oral Syrup helps promote regular bowel movements and supports gut health.

Lactulose Oral Syrup is used to treat the following conditions: 

1. Constipation  
2. Irregular bowel movements  
3. Hepatic encephalopathy associated with liver disease    

More Common

1. Bloating  
2. Gas (flatulence)  
3. Stomach cramps  
4. Nausea  
5. Diarrhea  
6. Abdominal discomfort      

Less Common 

1. Severe diarrhea  
2. Dehydration  
3. Electrolyte imbalance  
4. Vomiting  
5. Severe abdominal pain  
6. Allergic reactions (rash, itching, swelling) 

Lactulose is a synthetic sugar that is not absorbed by the body. It reaches the colon unchanged, where it is broken down by beneficial bacteria into organic acids. These acids draw water into the bowel, soften the stool, and stimulate bowel movements. In liver disease, Lactulose lowers ammonia levels by trapping ammonia in the colon and helping remove it through the stool. 

Allergy/Hypersentivity

If you are allergic to Lactulose or any ingredient in this medicine, avoid using it as it may cause allergic reactions such as rash, itching, or swelling.

Diabetes

Use Lactulose cautiously if you have diabetes, as it contains sugar-like compounds that may affect blood glucose levels.

Gastrointestinal Disorders

Patients with bowel obstruction, unexplained abdominal pain, or intestinal disorders should consult their doctor before using this medicine.

Dehydration Risk

Excessive use may cause diarrhea and dehydration. Drink plenty of fluids while taking Lactulose.

Pregnancy and Breastfeeding

Lactulose is generally considered safe during pregnancy and breastfeeding when used as directed by a healthcare professional.

Drink adequate water while taking Lactulose to help improve its effectiveness. There are no major food restrictions, but maintaining a high-fiber diet may help improve bowel regularity.

Avoid taking Lactulose Oral Syrup with the following medicines, as it may increase or decrease the desired effect, or in worse cases, it could be fatal:

IUPAC (International Union of Pure and Applied Chemistry)/ Chemical name

Lactulose: (2S,3R,4S,5R,6R)-2-[(2R,3S,4S,5R)-4,5-dihydroxy-2,5-bis(hydroxymethyl)oxolan-3-yl]oxy-6-(hydroxymethyl)oxane-3,4,5-triol 

Daily dose

Take Lactulose Oral Syrup exactly as your doctor recommends. The dose may change based on your condition and how well you respond. Do not take more than prescribed without consulting your doctor.

Missed Dose

If you forget to take your medicine, take the medication as soon as you remember. If it’s nearly time for your next dose, skip the missed one and continue with your regular schedule. Always consult the doctor before making any changes to your dosage.

Overdose

It is not recommended to take more than 40 grams of Lactulose Oral Syrup, as overdose may cause severe diarrhea, dehydration, stomach cramps, electrolyte imbalance, and weakness. Seek immediate medical attention if overdose symptoms occur.

1. Store the medicine at room temperature. 
2. Keep away from sunlight and moisture. 
3. Keep out of reach of children 

1. Take Lactulose Oral Syrup exactly as prescribed by your doctor, at the same time each day. 
2. Do not stop taking Lactulose Oral Syrup without your doctor’s approval, even if you feel better. 
3. If you forget to take Lactulose Oral Syrup, take them as soon as you remember. If it’s almost time for your next dose, skip the missed dose.

What are the uses of Lactulose Oral Syrup? 

Lactulose Oral Syrup is used to treat constipation by softening stools and making bowel movements easier. It is also used to manage hepatic encephalopathy in people with liver disease. 

How does Lactulose Oral Syrup work? 

Lactulose draws water into the colon, softens the stool, and stimulates bowel movements. In liver disease, it helps reduce ammonia levels in the blood. 

How long does Lactulose take to work? 

Lactulose usually starts working within 24–48 hours, although some people may notice improvement sooner or later depending on their condition. 

What are the side effects of Lactulose Oral Syrup?

Common side effects include bloating, gas, stomach cramps, nausea, and diarrhea. Severe diarrhea or dehydration may occur if too much is taken. 

1. Lactulose Dosage Guide with Precautions [Internet]. Drugs.com. Available from 
2. Mukherjee S, John S. Lactulose [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2024. Available from 
3. NHS. Lactulose [Internet]. NHS. 2019. Available from