Neonates who swallow a considerable amount of maternal blood may exhibit vomiting and suckling disorder during the first few days of the postnatal period. Some clinicians treat these neonates with gastric lavage (GL) to prevent vomiting and the establishment of enteral feeding empirically, but there was no study assessing the effect of GL for neonates with coffee-ground emesis. We designed a multicenter randomized controlled trial to evaluate the efficacy and safety of GL in neonates with coffee-ground emesis. Vigorous neonates with birth weight ranging from 2500 g to 3999 g and gestational age between 37w0d and 41w6d who presented with coffee-ground emesis on more than twice and diagnosed as false melena, were divided into two groups using computerized randomization. We defined feeding intolerance (FI) as (1) ≥2 vomiting episodes in 4h or ≥3 episodes in 24h and/or (2) feeding failure on at least two occasions because of retching or poor sucking. Primary outcome is percentage of infants who present FI within 24 hours from admission. We also assessed the residual volumes, number of vomiting episodes, percentage of weight reduction at postnatal day 4, rates of body weight gain at 1 month of age, and peak serum total bilirubin value before discharge. To our knowledge, this is the first study to evaluate the safety and efficacy of GL for neonates with coffee-ground emesis. This trial is registered at UMIN Clinical Trials Registry as UMIN000026483.