Trying to suggest the US should not accept any refugees, Donald Trump Jr posted an image that asked:
"If I had a bowl of skittles and I told you just three would kill you, would you take a handful?''
"That's our Syrian refugee problem."
He added: "This image says it all. Let's end the politically correct agenda that doesn't put America first."
The food analogy has been used before to imply that, if a few people in a group are bad, it would be dangerous to take a single one in.
The language in Donald Jr's tweet was used in a post by conservative radio host Joe Walsh in August.
But following the tweet by the Republican presidential candidate's son, the company that owns Skittles, Wrigley, stepped in.
"Skittles are candy. Refugees are people," said Denise Young, vice-president of corporate affairs for Wrigley America.
"We don't feel it is an appropriate analogy," she added. "We will respectfully refrain from further commentary as anything we say could be misinterpreted as marketing."
There has been no reaction from Donald Trump's campaign.
But Nick Merrill, Hillary Clinton's travelling press secretary, early tweeted that Donald Jr's post was "disgusting".
Angered by Donald Jr's statement, some people posted images of child refugees on their Twitter feeds.
Many of the posts both mocked the comparison and tried to highlight the plight of Syrians caught up in their country's civil war.
In a tongue-in-cheek article, Washington Post journalist Philip Bump did some calculations around Donald Jr's statement, using data showing that the annual chance that an American would be murdered by a foreign-born terrorist was 1 in 3,609,709.
Based on his sums, it would take about one and a half Olympic swimming pools of Skittles in order to find three killers.
Other people on Twitter used the meme to reflect on their feelings about the 2016 presidential race.
But many supporters of Trump and right wing commentators welcomed his son's message and hit out at the criticism online, referring to recent attacks in the US.
A series of bombings and stabbings in the US - deemed acts of terrorism by officials - have heightened security concerns in the country.
Donald Trump's hard-line stance on immigration and plans for combating Islamist extremism have drawn both cheers and condemnation ahead of November's presidential election.
In August he announced that he wanted to introduce ideological tests for those entering the US, and temporarily suspend visas for people coming from countries "compromised by terrorism".
The US has accepted at least 10,000 Syrian refugees so far this year, fulfilling a goal announced by President Obama in 2015.
Both President Obama and Democratic presidential nominee Hillary Clinton have insisted that closing the door to refugees would be against American values and have called for more to be accepted.