As antibiotics kill off infection-causing microorganisms, they also non-selectively destroy communities of beneficial gut bacteria, weakening the stability of the intestinal microbiome.The degree to which these drugs damage intestinal microbiota depends on drug type, treatment duration, and frequency of use. Certain antibiotics trigger a greater release of endotoxins and cytokines than others. Higher daily doses are more impactful. Prolonged use of high-dose antibiotics can cause extreme damage to the microbiome that can take years of restorative therapy to reverse if it can be reversed at all.Intravenous antibiotics can have the same negative impact on gut flora as oral drugs.The timing of antibiotic delivery also makes a difference. Individuals who frequently use antibiotics early in life are more vulnerable to many types of illness as they age. Antibiotics have also been associated with obesity and weight gain in children as well adults. Researchers attribute these changes to the altered gut microbial composition.Antibiotics can trigger the release of toxic lipopolysaccharides (LPS), large molecules found in the outer membranes of pathogenic Gram-negative bacteria. Some suggest that antibiotic-induced LPS release may contribute to the development of septic shock in patients treated for severe infections caused by Gram-negative bacteria. Others have demonstrated that LPS triggers an immune response by releasing inflammatory cytokines, a problem that worsens after antibiotic treatment.The production of LPS is a survival strategy. These molecules interact on cell surfaces to form a barrier, preventing the antibiotics and other hydrophobic compounds from entering and allowing Gram-negative bacteria to live even in harsh environments.