Antibiotics, when mixed to animal fodder promote more weight gain in food animals and it might have a similar effect on humans also. Antibiotics are not readily degrading, and might appear in drinking water and different vegetables, animal meat, etc. The concept of possible global effect of antibiotic pollution/consumption as an inadvertent effect on humans promoting growth and obesity was first raised in 2005. The parallel appearance of the noninfectious pandemics might raise the possibility of a common origin. It was suspected, that this common origin might be the alteration of gut flora as the inadvertent effect of antibiotic consumption/pollution. Large databases of obesity and antibiotic consumption figures were compared and it was found that childhood obesity is significantly associated with the consumption of broad spectrum antibiotics, particularly macrolides. Similar association in adults was not observed. This finding indicates, that the consumption of broad spectrum antibiotics, by altering gut flora, can strongly contribute in the pandemic of obesity and related type 2 diabetes along with autism, where obesity and the alteration of the gut flora is well documented.