In this Harm Reduction Digest Sheridan, Butler, Wilkins and Russell address the emergent phenomenon of so-called 'legal party pills' which have become a significant drug issue in New Zealand and elsewhere. Although banned in a number of countries, they are currently legally available in New Zealand where they are marketed as 'safe' alternatives' to 'illicit' drugs often used in the dance scene such as MDMA and amphetamines. The authors describe the availability and use of these substances in New Zealand, summarize what is known about their effects, and speculate on harm reduction interventions and mechanisms of control and their possible sequelae. The paper provides a timely account of an emerging drug issue of relevance to harm reduction internationally.