Probiotic supplements promise a healthier gut, but what happens if it become deadly? In a stunning Japanese case, a man's everyday probiotic set off a deadly bloodstream infection. The unusual but disturbing event has raised urgent questions about the safety of probiotics, particularly for people with underlying health issues. Is your gut-friendly supplement a silent danger?In a rare and unexpected case, a 70-year-old Japanese man developed a deadly bloodstream infection attributed to the very probiotic supplements intended to enhance his health. His case, which was reported in BMJ Case Reports, has sparked serious questions regarding the possible dangers of probiotics, especially for those with weakened health.The man, who had a history of alcohol dependence and underlying medical conditions, was found collapsed in his home and was rushed to the hospital. Upon examination, doctors diagnosed him with metabolic acidosis—a dangerous buildup of acid in the blood—triggered by a severe lung infection, kidney injury, and possibly heavy alcohol use.To his list of health issues, the patient tested positive for COVID-19. He was put in the ICU, where he was provided with intensive care, such as breathing assistance, a blood thinner, anti-inflammatory steroids, and tocilizumab—a medication used to suppress inflammatory proteins. In addition to treating a secondary bacterial infection, he was administered antibiotics, which caused diarrhea, a typical side effect.In an attempt to get his gut health back, doctors prescriped a probiotic with Clostridium butyricum, a naturally occurring bacterium in approximately 20% of healthy people. Although considered safe, the probiotic unexpectedly and fatally turned in his instance.For nearly two months, the patient appeared to be recovering. However, he suddenly developed severe fatigue, swelling, and persistent abdominal pain. Body scans revealed a life-threatening reduction in blood flow to his intestines—a condition that often results in tissue death and organ failure.As his health worsened, blood work was done, and an alarming finding was discovered: C. butyricum bacteria were found in his blood. This was a definite indication of probiotic-associated bacteremia—a rare but reported side effect in which bacteria from a probiotic supplement get into the bloodstream and infect the body. Genetic testing proved that the strain in his blood was the same as the one in the probiotic he had been consuming.In spite of medical treatment, the patient's condition deteriorated quickly. His immune system, already compromised by his medical history of colon cancer, high blood pressure, heart disease, and smoking, could not combat the infection. Because of his unstable status, surgical intervention was not possible. In a matter of days, he had multiorgan failure. With no other medical options available, physicians switched him to palliative care, and he sadly died on the 60th day of hospitalization.How Might a Probiotic Supplement Become Lethal?Probiotics are frequently utilized to maintain gut health, particularly following antibiotic use. Probiotics replace beneficial bacteria, enhance digestion, and alleviate inflammation. In rare instances, however, probiotics may break through the gut and enter the blood, causing severe infections. This is more likely in people with compromised immune systems, chronic disease, or underlying gastrointestinal disease.A number of studies, one of which was released in 2019, have established genetic associations between probiotics and hospital patient bloodstream infections. This case contributes to mounting evidence that while probiotics are generally good for many people, they can be dangerous for susceptible populations.Who Is Most at Risk?Though probiotic infections are unusual, some groups are at greater risk, which includes:Older patients with multiple comorbidities: As in this case, older patients with comorbidities are at increased risk of developing serious complications.Patients with compromised immune systems: Diseases like cancer, chronic kidney disease, and autoimmune diseases raise the risk of infection.Critically ill or hospitalized patients: The combination of several treatments, including steroids and immunosuppressive medications, can further increase the risk.Individuals with gastrointestinal abnormalities: An existing gut problem makes it simpler for probiotics to cross the intestinal barrier and get absorbed into the blood.Should You Stop Eating Probiotic Supplements?Even with this unfortunate case, health specialists highlight that probiotics are still safe for most healthy individuals. Nevertheless, they advise using probiotics cautiously, especially in high-risk patients.Experts point out that although probiotics are prescribed to patients suffering from gastrointestinal conditions, rare but serious side effects can take place. He emphasizes that healthcare practitioners should screen a patient's history before they suggest probiotics, particularly in a hospital setting.Probiotics are commonly lauded for their shield against colds, digestive problems, and severe health ailments. Their advantages are still controversial, though. A new study conducted by UC San Francisco researchers contradicts the notion that probiotics, in particular the Lactobacillus strain, ward off eczema—a disease commonly associated with asthma.Probiotics, which exist in supplements and foods that are fermented such as yogurt and kefir, are believed to help promote the health of the gut by enhancing immune function and suppressing disease-causing pathogens. According to the World Health Organization, they are "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host."Released in Pediatrics on August 7, 2017, the research surveyed high-risk asthma infants. Comparing those supplemented with probiotics for six months to those that were not supplemented, researchers saw no apparent effect that probiotic supplementation has in lowering the risk of eczema, fueling the continued controversy surrounding their actual health effects.