Medical writing tends to contain longer, less common, words than English fiction, and they are here termed troublesome words. Troublesome words are an indicator of poor style, and often point to grammatical errors. An easy way to start improving one’s writing is to look for these troublesome words and replace them with shorter, more common, synonyms. From quantitative analysis of medical and general English, lists can be drawn up of common troublesome words, and of troublesome words whose prevalence is increasing particularly in medical English. The words discussed here are novel, demonstrate, exhibit, explore, quantify, evaluate, option, perform, execute, represents, and target. Exercises are provided, and readers are encouraged to seek out poor medical writing and to improve it.