Probiotic bacteria, coloured scanning electron micrograph (SEM). Probiotics are defined as live microorganisms that are believed to provide health benefits when consumed. Lactobacillus species may be taken for general digestive and urogenital problems. Lactobacillus taken during and after a course of antibiotics may decrease the chances of subsequently development of opportunistic infections from unwanted gut bacteria. Magnification: x5000 when printed at 10 centimetres wide.