Grief — the response to the loss of a loved one, of meaning, of a way of life — sits at the intersection of psychological, cultural, biological and existential dimensions. In recent years, scientific interest has grown in whether certain psychoactive plants and medicines, used in adequate contexts, may help people process complex or prolonged grief. ICEERS gathers here content on grief, including research on ayahuasca-assisted psychotherapy for prolonged grief and on end-of-life care.