OBJECTIVES: Polygonum hydropiper is a herb with worldwide distribution, having tremendous value as traditional medicine among different communities. It is used to cure many kinds of ailments such as gynaecological disorders, ulcer, anxiety, pain, cancer, etc. The present review gives emphasis on a thorough and updated study of the botanical description and taxonomy, distribution, habitat, ethnopharmacology, phytochemical constituents, pharmacological activities and toxicological aspects of P. hydropiper. METHODS: The information included in this review was collected from different scientific databases like PubMed, ScienceDirect, Google Scholar, etc. In addition to the botanical description and taxonomy, lots of ethnomedicinal use of the water-pepper plant could be found. RESULT: A good number of compounds belonging to the categories like alkaloids, carbohydrates, flavonoids, etc. were confirmed to be present in the plant. Moreover, in different studies, this plant was found to possess activities like anti-Alzheimer, antibacterial, antidementia, antifertility, neuropharmacological, sedative, anxiolytic, thrombolytic and membrane-stabilizing activity, etc. with minimal toxicity. CONCLUSION: These properties may be directly related to its possession of a large number of bioactive molecules of different categories. Based on these properties, isolation of responsible compound(s), evaluation of molecular mechanisms of their action and clinical trials are recommended. CI - (c) The Author(s) 2022. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.