When dosing any med cann products (i.e. vape-pen, tincture drops, etc) the dosing requirements will depend on a variety of factors including the pt's sex, height & weight, previous experience with cannabis, and level of nausea induced by the chemo-therapy agents. In general, I share the concept of "minimum effective dose/ concentration" with cannabis. The idea is to slowly add more/ re-dose until the moment the nausea disappears. For tinctures, a good place to start is the product label; most tinctures I've seen give general dosing guidelines based on weight etc (i.e. half dropper vs full dropper). Another wrinkle I add for nausea patients using tincture is to try dilution in hot non-caffeinated tea. In this case, however, I tell patients to use a slightly larger-than-normal dose since the tincture drops are being diluted in a larger volume of hot soothing tea. I hope these tips prove useful!