Tylenol with Codeine and Breastfeeding: What Does the Research Say? The acetaminophen (Tylenol ®) component of Tylenol with Codeine passes through breast milk, but it is not likely to cause problems (see Tylenol and Breastfeeding). Codeine phosphate (the . Tylenol with Codeine #3 use while Breastfeeding Important: Tylenol with Codeine #3 is a drug containing multiple ingredients. Please check each of the links below, where breastfeeding (lactation) information is available. This information is not intended as a substitute for professional judgment.