Sulfur farts are caused by intestinal bacteria that produce compounds containing sulfur. Most farts are caused by swallowed air or healthy gut bacteria that break down food in the digestive system. However, there can be more serious causes of rotten-smelling gas. Here are some common causes of sulfur farts:

• High-fiber foods: Many high-fiber foods can cause you to pass more gas. It takes longer for these foods to break down in your digestive system, so they ferment over time. High-fiber foods also sometimes smell, which means your farts may smell, too. This is especially true with strong-smelling vegetables, such as broccoli, Brussels sprouts, cauliflower, and cabbage. Your gas may smell like rotten eggs because of the sulfur in fiber-rich foods.

• Food intolerance: If you have a sensitivity or reaction to certain foods, your gas could have a foul odor. For example, people with lactose intolerance can’t break down the sugar lactose. As a result, it’s fermented by bacteria in the gut. Gluten-related disorders, including celiac disease, can also cause smelly farts. Celiac disease is an autoimmune disease where there is an immune response to the protein gluten. This leads to inflammation and injury in the intestine, leading to malabsorption and flatulence.

• Medications: Certain prescription drugs, vitamins, and supplements can cause foul-smelling gas. The reason they cause smelly gas differs by drug and person to person. Iron supplements are known to cause gas and bloating. Supplements containing fiber and some diabetes medicines can also make you gassy.

• Bacterial infection: If you have a bacterial infection, it can cause your farts to smell bad. Visit your doctor to determine if you have a bacterial infection. If you do, they’ll prescribe antibiotics to clear the infection and get you feeling better.

• Colon cancer: A rare cause of stinky gas is colon cancer. When polyps or tumors develop in the digestive tract, it can cause a partial blockage which can result in gas build-up and bloating. As always, you should check with your doctor for diagnosis.

To prevent sulfur farts, you can modify your diet by reducing your intake of high-sulfur foods such as eggs, meat, and cauliflower. If you have a food intolerance, you can avoid the foods that trigger your symptoms. If you suspect your foul-smelling gas is a symptom of a larger problem, your doctor can help diagnose the cause and create a treatment plan.