I have a friend who has a chest infection and instead of switting out the phlegm he swallows it.He's complaining of a tummy ache now and I was wondering if this could be the reason?

Swallowed phlegm is not harmful.  Excessive swallowing may introduce excessive air into the GI tract and cause gas pain.

Filariform larvae penetrate human skin, reach the lungs via blood vessels, penetrate into pulmonary alveoli, ascend the respiratory tree to the epiglottis, and are swallowed. The larvae develop into adults that attach to the wall of the small bowel, feeding on blood.

Thus you can see that most worms in filariform larvae reach the intestine from lungs via pharynx. If you swallow sphlegm, filariform larvae will also go down to the stomach. Moreover if you got stomach ulcer, the bacteria present in the sphlegm may also likely to contaminate the ulcer.

Yes swallowing phlegm is bad for you. It will and can make the cold worst and last longer.  In order to feel better you must get rid of it (spit it out). I have a child that does that to help her get it out  I let her have milk products.  Milk never fails to sit on top of that phlegm and makes her  get rid of it.

Eww to the comment above(ehrstabk), no its not bad for you it does you good to get rid of it but its best spat down the toliet as it can give tummy upsets if you keep swolleing it but its not harmfull

its not harmful, it comes from your body so it wont harm you. but it is gross. your friend will feel a lot better if they spit it out and get rid of the infection.

It's not gonna kill you but it's not that good for you either. It's gross.

It isn't bad if you like it.

Only if it is someone else's.



Some of the Japanese videos on Youtube are a step too far...

yesit does cause stomache aches