This study compared five individuals who intentionally ingested formaldehyde (possibly laced with PCP) in marijuana cigarettes to a control group on measures of cognitive ability. Formaldehyde, a major component in embalming fluid, is legal to purchase and possess and has become popular due to its euphoric properties. In significant doses, the chemical is a neurotoxin. The effects of inadvertent exposure are fairly well known, but the effects of intentional ingestion have only recently been investigated. In addition, there has been little research on the effects of formaldehyde use specific to intellectual ability and cognitive intactness. The results of this study indicate intentional ingestion may cause a decline in neuropsychological intactness, as measured by performance on the Shipley Institute of Living Scale.