What is the minimum recommended dosage? Is there a risk of overdosing?

In literature it is reported that the maximum dosage used on human beings is 1500mg CBD/day, with good tolerance and without any particular side effects. In general research studies report that CBD has low toxicity. As of today no data has been registered in literature which analyse the risks of overdosage related also to other factors, amongst which the presence of particular pathological conditions and the simultaneous intake of certain types of medical drugs.