It is very common for babies to experience mild vomiting or spitting up as their digestive systems adjust to solid foods. Please do not give him any over-the-counter anti-vomiting medications, as these are not safe for infants without a doctor's prescription. For now, temporarily pause solid foods and focus on keeping him hydrated with small, frequent feedings of breast milk or formula. Keep him upright for 20 to 30 minutes after feeding. When you restart solids, introduce only one simple, single-ingredient food at a time. Please consult your pediatrician if he cannot keep breast milk or formula down, shows signs of dehydration (like dry diapers), or seems unusually lethargic.