As with traditional scholarly publications, the quality of Open Access works can vary considerably. Before citing or otherwise making use of an OA work, you should critically evaluate it.
Predatory journals are "entities that prioritize self-interest at the expense of scholarship and are characterized by false or misleading information, deviation from best editorial and publication practices, a lack of transparency, and/or the use of aggressive and indiscriminate solicitation practices" (Grudniewicz et al).
When evaluating an OA work, consider the following checklist:
You can also check whether the journal is included in a whitelist such as DOAJ, or use a tool such as Think. Check. Submit.