Experts have slammed a group of mums who boasted about feeding their babies "knockout bottles" designed to make them sleep for a long period of time.
Some parents are creating "dangerous" concoctions of breast milk or formula mixed with cereal, baby food or medicine.
One child nutritionist has called the idea a "choking hazard".
The "knockout bottle" first came to light after a New York mum posted to Facebook saying she made up a bottle that contained Tylenol (a pain relief drug) when her little boy was unwell.
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In her post, she said it has worked "every time".
"Y'all parents today! Don't know these knockout bottles! Sh*t worked every time. Especially when [the baby] is sick, add some Tylenol. Awww man out like the kite," she wrote, alongside a photo of the concoction.
The woman's admission sparked controversy from other parents who slammed the idea as dangerous.
"Feeding a baby a knockout bottle is literally horrible," one wrote.
Another said: "That is disgusting, and very dangerous to any child! Who let these idiots ever take a baby home from the hospital? This goes far beyond bad parenting."
While some parents are supportive of the "knockout bottle", childhood nutrition consultant Charlotte Stirling-Reed told The Sun the bottles put babies at risk of choking.
"It's not ideal and not recommended to offer babies solid foods from bottles.
"The action of drinking milk is very different to the action of swallowing solid foods, and therefore this could potentially put babies at risk of choking."
She also said milk formula needed to be made to a specific measurement, warning changing it up could be harmful.
Baby expert Jill Irving agreed, warning that tampering with babies' food would not always put them to sleep.
"The main reasons being it can cause choking or a baby to overeat and hence have an inappropriate weight gain," she said.
"There are absolutely no guarantees that a baby will sleep just because food has been added to the bottle."