Abstract: Solid forms comprising a compound useful in the treatment, prevention and management of various conditions and diseases are provided herein. In particular, the invention provides solid forms comprising (?)—O-desmethylvenlafaxine, including salts thereof, having utility for the treatment, prevention and management of conditions and disorders including, but not limited to, affective disorders such as depression, bipolar and manic disorders, attention deficit disorder, attention deficit disorder with hyperactivity, Parkinson's disease, epilepsy, cerebral function disorders, obesity and weight gain, incontinence, dementia and related disorders.