Background - Patients with inborn errors of metabolism causing fasting intolerance are at risk of acute metabolic decompensations. Disease specific emergency protocols are widely available, but long-term data on safety and efficacy outcomes are lacking. We hypothesized that a generic emergency protocol can be safe and effective in patients with inborn errors of metabolism causing fasting intolerance. Results - We retrospectively evaluated our generic emergency protocol in 128 patients with a hepatic glycogen storage disease or fatty acid oxidation defect between February 1, 2014 and April 24, 2019. In total, 127 hospital admissions were documented in 54 out of 128 patients (42%). Hypoglycemia (glucose concentration <3.9 mmol/l) was reported in 15% of admissions. Hypoglycemia at admission was uncommon in patients with ketotic glycogen storage disease and verbal patients with a fatty acid oxidation defect. Convulsions, coma or death were not reported. Conclusions - Generic emergency protocols can be safe and effective for home management by the caregivers and the first hour in-hospital management of metabolic emergencies in patients with hepatic glycogen storage disease and medium-chain Acyl CoA dehydrogenase deficiency.