Rationale Over-the-counter drugs containing hypericum perforatum (H. perforatum), have been argued to improve memory and sustained attention. So far, these claims have not been supported in human studies. However, previous studies used rather high dosages, and little is known about the acute effect of small dosages.

Objective We evaluated whether an acute treatment with Remotiv 500 and Remotiv 250 (500 or 250 mg of H. perforatum quantified to either 1 or 0.5 mg of hypericin) improved memory, sustained attention, as well as mood and state anxiety in healthy adults.

Method A single dosage, randomized, double blind, placebo-controlled trial was conducted with 82 student participants (33 women). Each participant received placebo in one session and one of two dosages in the other session. Order of the sessions and dosage conditions were randomized between subjects. Participants completed a battery of tasks assessing short-term memory capacity and sustained attention.

Inclusion Criteria:

• healthy adults 18 to 40 years old.

Exclusion Criteria:

• 1. Demographics: Under 18 years of age or older than 40; pregnant or nursing women; non-fluent Hebrew speakers.

  2. Body weight: less than 50 kg and more than 90 kg (to ensure effective drug dosage).

  3. Mental health: Diagnosed with any DSM-V disorder (including ADHD, learning disabilities). These DSM-V disorders may be included in the research: sexual dysfunctions, sleeping disorders and mild-moderate anxiety disorders.

  4. Any motor disability hampering a participant's ability to perform the experimental task.

  5. Consumption of any psychoactive substance within the last 72 hours. 6. Ongoing medical problems or use of any substances (e.g., other prescribed medications) which may interact negatively with any of the three drugs used in the experiment.