In acute, postoperative endophthalmitis it is essential to inject antibiotics at the site of the problem--i. e. intravitreally--to achieve the highest possible concentration. At the same time a vitreous tap must be taken before injection. According to the actual ESCRS guidelines, the practical procedure is described in this review. An additional systemic administration of antibiotics should be considered in cases where repeated intravitreal short-term injections are not administered. Additionally, systemic corticosteroids should be given to minimise the immune-associated inflammatory destruction.