Drinking too much cola can cause everything from mild weakness to muscle paralysis, as it can cause blood potassium to plummet, doctors are reporting in the International Journal of Clinical Practice. In it, they report on an Australian farmer who needed emergency care for lung paralysis after drinking up to 10 litres of cola a day (he fully recovered). In another case, a pregnant woman who drank up to three litres a day for six years was found to have an irregular heartbeat, likely caused by low blood potassium levels. She recovered fully after cutting her cola intake. Experts say soda’s three most common ingredients (glucose, fructose and especially caffeine) are likely to blame, the BBC reports, while manufacturers say soft drinks are safe when consumed in moderation.