Sodium citrate in its liquid formulation is commonly used as therapy for renal tubular acidosis in pediatric patients. Convenient dosing and administration is important to ensure long-term medication adherence and normal growth in the chronic forms of this condition. Liquid sodium citrate formulations contain propylene glycol, a commonly used excipient, which can be toxic at high doses. Propylene glycol toxicity due to medication excipients has been reported in the literature, including many cases secondary to sustained exposure to intravenous anti-epileptics, however toxicity associated with oral sodium citrate therapy has not been described. We report the first case of propylene glycol neurotoxicity in a 6-week-old infant with renal tubular acidosis treated with sodium citrate. Clinical suspicion of risk for medication-related toxicity and awareness of propylene glycol content in sodium citrate led to timely diagnosis and management. Awareness of increased risk of toxicity in pediatric patients due to high sodium citrate requirement and low propylene glycol metabolism capacity is important for optimal care for pediatric patients with renal tubular acidosis.