First-time parents have so much to worry about, from what food they should be feeding their newborn to whether their child is sleeping in the right position. They also have to worry about their child becoming ill, and often keep an eye out for any signs that something is coming on. But many of them tend to worry too much, blowing small signs like a cough or two out of proportion, and contacting a doctor just to be cautious. It turns out agave nectar is good for treating infants’ coughs, but not how you may think.

Researchers from Penn State College of Medicine found in a new study that the sweet syrup, extracted from the agave plant, works well when a child has a cough. But it’s not actually the cough that’s being treated. Rather, it’s the parent’s fears. During their study, a placebo and agave nectar were both used to treat acute coughs, but while they were equally bad at putting an end to the cough, parents perceived them as effective — a placebo effect.

“Both physicians and parents want symptomatic relief for children with these common and annoying illnesses,” the researchers wrote, according to a press release. “The significant placebo effect found warrants consideration as health care providers and parents determine how best to manage the disruptive symptoms that occur in the setting of upper respiratory tract infections among young children.”

More children under 4 visit a family doctor for acute coughs than any other illness, according to a systematic review published in the British Medical Journal. There’s a good reason for this; it’s hard to determine the cause of a cough. It could be anything from the common cold to pneumonia, or an upper respiratory tract infection to whooping cough — a deadly bacterial infection. But although it’s more often than not anything serious, many parents still want medicine. Yet, the Centers for Disease Control and Prevention stresses that children shouldn’t get antibiotics because even if they ease symptoms, they could be detrimental to health over time.

The researchers set out to trick parents over just one night, treating 119 children aged 2 to 47 months suffering from a nighttime cough with either agave nectar, grape-flavored water, or nothing at all. Though they didn’t really do much, the children’s parents believed that they were effective in reducing coughs. Sometimes, that’s all that really matters.

Source: Paul I, Beiler J, Vallanti J, Duda L, King T. Placebo Effect in the Treatment of Acute Cough in Infants and Toddlers: A Randomized Clinical Trial. JAMA Pediatrics. 2014.