Consuming too much of probiotics can cause brain fogginess and disorientation, as well as rapid belly bloating, according to scientists - including one of Indian origin - who advise people against self-prescribing 'good' bacteria. In a study of 30 patients, researchers found that 22 who reported problems like confusion and difficulty concentrating, in addition to their gas and bloating, were all taking probiotics, some several varieties.

When the researchers looked further, they found large colonies of bacteria breeding in the patients' small intestines, and high levels of D-lactic acid being produced by the bacteria lactobacillus' fermentation of sugars in their food, said Satish S C Rao, from Augusta University in the US. While probiotics can be beneficial in some scenarios, like helping a patient restore his gut bacteria after taking antibiotics, researchers advised caution against its excessive and indiscriminate use. "Probiotics should be treated as a drug, not as a food supplement," Rao says, noting that many individuals self-prescribe the live bacteria, which are considered good for digestion and overall health.