Firms often manipulate online reviews to influence consumer perceptions of products. We examine how consumers perceive and respond to three common manipulation tactics. Firstly, an exploratory study via in-depth interviews indicates that consumers are aware of online review manipulations and can detect them to various degrees. In study 2a, a survey indicates that consumers rate hiding/deleting unfavorable reviews the most deceptive and unethical, followed by anonymously adding positive messages, and incentivizing favorable reviews. In study 2b, a simulated field finds that review manipulation increases suspicion but hardly reduces purchase intention. Persuasion knowledge of consumers leads to suspicion, but lessens the negative impact of suspicion on purchase intention. The third study uses secondary data of a branded e-retailer and its third party website to cross-validate the effect of manipulations on product sales. The results indicate that review manipulations are effective to some extent in increasing sales; however, the effect decreases over time in an inverted U-curve. These findings provide valuable insight to practitioners and policy makers on the pitfalls of online manipulation activities and the need to ensure the healthy development of e-commerce.