The prevalence of alcohol use disorder was found 75% higher among amphetamine dependent patients. Alcohol and amphetamine alone have nephrotoxicity and hepatoxicity. But, the degree of risk with coabuse of alcohol and amphetamine is unknown. The objective of this study was to assess toxic effects of amphetamine-alcohol co-abuse on the liver and kidney. he present study was a cross-sectional study conducted et al. Amal Hospital for Mental Health, Qassim region, KSA and include one hundred participants. Seventy-five participants were patients hospitalized for the treatment of abuse, and twenty-five participants, were healthy voluntaries, have no history of abuse. An experienced psychiatrist conducted patient interviews and assessed the patients using the DSM-5 criteria. The data from healthy participants were considered as a control. The abuse group was paired with the control group by age and lifestyle. Participants were split into: Group I: Control group (n = 25); Group II: Amphetamine (AMP) abuser group (n = 25); Group III: Alcohol abuser group (n = 25) and Group IV: Combined drug abuser group (AMP and alcohol) (n = 25). The socio-demographic data was collected. Complete medical examination, Body Mass Index and samples of blood and urine were collected from all participants for analytical tests; determination of alcohol and AMP levels, kidney functions and liver functions. The mean BMI values in groups II, III, and IV showed no significant change from the control group. The serum level of albumin and alkaline phosphatase showed significant decrease in all abuser groups. While, alanine transaminase (ALT), Aspartate transaminase (AST) and osteopontin levels showed significant increase in all abuser groups. Fasting blood sugar values showed significant increase in alcohol abusers. On the other hand, it revealed no significant change in AMP and combined groups. The mean values of urea showed no significant change in AMP and alcohol abusers and significant increase in combined drug abuser group. The serum creatinine and all abuser groups showed significant increase in Cystatin C. The alteration in the most of studied biochemical parameters were more than two folds in combined group compared with that of AMP or alcohol groups. Study reveals synergistic liver and kidney toxicity. Amphetamine-alcohol co-abuse significantly heightens kidney and liver toxicity.