The answer

Loperamide capsules or bismuth subsalicylate – the ‘pink stuff in a bottle’ – would not be good options in this case, as the diarrhoea Anya is experiencing has mucus in it. This, alongside her other symptoms of abdominal pain and fever, suggests that she has invasive diarrhoea. As she has recently returned from Thailand, there is a chance she picked up a bug while she was out there, and as her symptoms have persisted for so long she should make an appointment to see her GP. She will probably be asked to provide a stool sample, which will be tested for microbial pathogens so that she can be given a course of antibiotics, if necessary.

Anya also needs to make sure that she does not become dehydrated by drinking plenty of clear fluids such as water, diluted fruit juice or reconstituted oral rehydration therapy sachets, and steering clear of alcohol and caffeine. 

If she feels able to, she should eat small, light meals, such as boiled vegetables, plain rice, soup or potatoes, avoiding fatty and spicy foods. 

It is also sensible to ask Anya if she is taking any medication because severe diarrhoea can alter the effectiveness of some drugs (e.g. the oral contraceptive pill and drugs for epilepsy).