Plant food supplements (PFS) receive great acceptance by European consumers. However, quality and efficacy of these products remain a question of concern. The aim of this systematic review is to summarize and critically evaluate the evidence for or against the efficacy of PFS for coping inflammatory conditions by considering epidemiological and human intervention studies. The review, which consists of two parts, considers Olea europea L., Camellia sinensis L., Vitis vinifera L., and Matricaria recutita L., which are herbal material frequently used also as food. The search retrieved 1251 publications. By applying the inclusion/exclusion criteria, the final number of papers was 91. Vitis vinifera L. showed promising results, but other trials should be performed in order to assessing the efficacy. Surprisingly, it was impossible to draw conclusions for the anti-inflammatory effect of Camellia sinensis L. as green tea. No studies were found on the leaves of Olea europea L. whereas more human trials are needed to assess the anti-inflammatory effect of olive oil. Only one study for Matricaria recutita L. was selected. In conclusion, it is advisable to conduct further studies with more homogeneous population and larger number of subjects by avoiding the heterogeneity of the herbal preparations considered.