Substandard medical products are products that fail to meet either their quality standards or specifications and are, therefore "out of specification". This WHO Medical Product Alert refers to one batch of substandard (contaminated) METHOTREXTM (methotrexate) 50mg, identified in two countries (Yemen and Lebanon). The microbiological testing on the unopened vials of METHOTREXTM 50mg were positive for Pseudomonas aeruginosa which can cause bloodstream infection which is a serious infection and may lead to death. WHO requests increased surveillance and diligence within the supply chains of countries and regions likely to be affected by this product.