Vad orsakar extremt illaluktande fisar?

I promise I will try to get through this without resorting to double entendres, although given the subject matter it will be difficult. Many of us will have been the butt (you see?) of schoolboy humour. More polite options don't quite fit the bill, though. 'Passing wind' sounds like something a country and western star would sing about, and 'letting one go' sounds more like a job release than a gas release. So let's call a fart a fart and be done with it.

Getting to the guts of the problem

Patient 1 posted a forum message to say that for the last two months she had been getting really bloated and passing the most foul-smelling gas ever.

She ate healthily, exercised regularly and was not overweight. Doctors had tested a stool sample but found it clear. She was told she had IBS and was prescribed Colofac® (mebeverine) tablets but these didn't help.

She had to air her bungalow every evening. She could not have visitors, had given up her job and was getting seriously deprimerad.

Patient 1 is clearly not alone. Her posting attracted 247 replies.

21st century doctors are supposed to go on about changes in lifestyle as well as pushing pills and whilst this condition is no different, it's always worth ruling out treatable underlying causes. Patient 2 suggested getting tested for celiaki. Other causes can include divertikulit (when small pouches in the wall of the large bowel, called 'diverticula', become infected) and sklerodermi, a condition which causes thickening of the skin and sometimes the internal organs.

Patient 3 wanted to make the forum aware that äggstockscancer can lead to bowel symptoms and that bloating in women over 40 shouldn't be ignored. Patient 4 noticed her smelly farts were caused by gabapentin, an anti-epileptic medicine. Other medicines that can do this are metformin, used for diabetes, and lactulose, a laxative.

What goes in must come out, and we mustn't forget simple mechanics. Swallowing too much air (aerophagy) often results in burping, but if the air gets trapped lower down the gut, it can only travel downwards. Stress, chewing gum, and rökning can all be associated with excessive air swallowing.

Food for thought

Forum posters identified many dietary factors which made the problem worse. Patient 1 found that spaghetti Bolognaise, shepherd's pie and curry were the main offenders. Patient 5 mentioned laktosintolerans, in which the body has difficulty digesting lactose, leading to bowel symptoms. Patient 6's problem was made worse by tuna and salmon, and Patient 7 found it best to avoid dairy products.

Studies have found that the main culprits seem to be broccoli, Brussels sprouts, starchy foods such as potatoes, corn and noodles, and foods high in soluble fibre (eg, fruit, peas and beans). Other foods or beverages that have been implicated include fizzy drinks and whole grains. Patient 8 identified fructose as being a trigger. This is found in fruit, artificial sweeteners and corn syrup used to sweeten many foods.

The best approach is to keep a diary and see if you can match your symptoms to any particular foods or drinks and try avoiding them for a while.

Patient 9 found that taking probiotika was helpful and this does have some support in the scientific world.

The answer is blowin' in the wind

There's no one solution to this problem but forum posters have come up with several suggestions, several of which are supported by medical evidence. Charcoal tablets seem to be a popular choice. They can be bought over the counter and are meant to absorb gas in the bowel. They are not the answer for everyone, however; Patient 10 found they only helped if plenty of water was drunk and they didn't work for Patient 11 at all. Patient 12 got some benefit from a pair of underpants with a charcoal pad to absorb the smell. Carbon underwear is said to be more effective.

Patient 13 recommended Pepto Bismol®. This is OK when taken occasionally for social occasions, but side effects such as förstoppning and dizziness limit its use.

Patient 14 found pepparmynta useful. This has an effect on the movement of muscles in the gut. Other medicines with this effect are available on prescription.

Mebeverine och alverine combat gut spasms and are available over the counter. Simeticone may also be worth a try. It is also available over the counter and is said to break up bubbles in the stomach but the scientific evidence supporting it is weak.

Forum posters have come up with other suggestions which they have found helpful from their own experience. Patient 15 recommends chewing cumin seeds, mrskiranaya advocates chiropractic (it's all to do with hip alignment, apparently) and Patient 16 swears by turmeric. None of these is supported by vast amounts of scientific evidence but I've always been fairly laid back about unconventional treatments, providing they don't do any harm.

There. I managed to get through this feature without any unintentional double entendres. Hopefully, you'll find it helpful in getting to the bottom of your problem.