Companies face increasing peril to their reputations – and sales — as online rumors and misinformation proliferate.

Take the example of Purina, the pet food maker.

Complaints that its food has caused illnesses in pets have proliferated online in recent weeks. Those assertions took off on a Facebook group called Saving Pets One Pet @ A Time. The group administrator posted that she had received many reports of dogs or cats growing ill or dying after eating Purina Pro Plan. Posts on TikTok followed.

Purina says there are no problems with its food.

The online chatter caught the attention of NBC News, which wrote about the issue and quoted the Facebook group administrator claiming she has received 969 reports of dogs or cats growing ill after eating Purina food.

The company told NBC the Facebook group hasn’t provided Purina with details about the complaints it received, and a company spokeswoman was quoted saying that a veterinarian who partners with another dog food brand is one of the Facebook group’s administrators. The veterinarian told NBC that she recommends multiple brands of pet food and that she isn’t trying to make money off of the Purina assertions.

In such situations, companies need to respond aggressively and transparently on the platforms where the misinformation is spreading – with as many facts as they can muster to prove the allegations false.

Unfounded allegations can spread so rapidly that responding quickly is essential. Additionally, there are usually a small group of people responsible for spreading rumors and misinformation. Companies need to identify them, determine their motivation, and address them directly.

In this case, Purina could consider having samples of its food tested by a third party and posting the results online. Purina also could hire third-party investigators to examine its factories and make the findings public. And the company could consider responding online to all of those propagating the assertions, pressing for details that would allow it to investigate.

Consumers need to see that companies are taking their concerns seriously and being forthcoming with their findings.