The occurrence of treatment failures to first-line treatment for giardiasis, one of the most widespread although neglected parasitic disease, has long been recognised. Nowadays, it starts to represent a great challenge to clinicians, especially in endemic countries. This requires the introduction of new drug interventions, but the development of novel drugs is a time and money consuming effort with most of the compounds never reaching the market. Consequently, alternative strategies are needed, especially for the treatment of giardiasis. Chloroquine (CQ), a synthetic drug developed as antimalarial agent, has been shown to also exert antigiardial activity. Here, we present a mini-research summarizing results on the treatment of human clinical cases with CQ, going through in vitro research, case report, and case series to human clinical trials, highlighting the benefits and mentioning possible adverse effects.