On Thursday, Dillard posted a picture to his Instagram account showing the couple's 6-month-old son, Sam, sitting in a car seat and playing with his new "toy," a water bottle.
"Sam loves his new toy! Number 3 on top gifts for 6-month olds for 2018. Trending up from number 4 gift since 1950. #cheapentertainment," the reality star wrote.
Fans of the TLC star took issue with the infants "toy," going as far as accusing Dillard of putting his son's life in danger.
"Be careful with those bottle. My daughter gave her 7-month one and somehow the lid came off. If we hadn't of seen it, she could have choke," one commenter warned.
"It's very dangerous for a small child to do that. I bet you can ask any Dr and they'd say no not to let them have a bottle with a small lid. If he can hold it, give him a actual toy or let him play with a empty sippy cup," one user wrote.
Others, however, were much harsher with their criticism.
"What are wrong with these people? Do they not look at the tube and see that there's a poison control # to call. Wouldn't that give you a hint NOT to chew on a tube of but cream and if you've used it too, ewwww. Imagine the germs on the outside," one person commented.
One person even accused Dillard of exposing his son to deadly toxins, writing "There are toxins in plastic, Derick. Are you an idiot?"
This isn't the first time Duggar and Dillard have come under the microscope for their parenting. Earlier this month, fans called them out when a pictured showed Sam lying on a carpet that some deemed to be "dirty."
While the couple is constantly facing scrutiny, their upcoming break from the spotlight may help. Both Duggar and Dillard will be leaving reality TV behind. When Counting On returns at the end of February, the Dillard family will reportedly no longer be a part of it.
The separation came after Derick Dillard made some unwarranted and offensive comments about Jazz Jennings, another TLC star. The network reacted quickly, announcing that they'd fired Dillard and he wouldn't be returning to the show.
Dillard, for his part, took his outrage to Twitter, saying that he hadn't been "fired," but he'd "decided" to get his family off of the show. This means that Dillard is likely taking his wife and kids with him in his departure from TLC.