Dog walkers in Lytham and St Annes are being warned after palm oil washed up on beaches along the Fylde coast.
The potentially deadly lumps of palm oil were found on St Annes beach on Wednesday morning (January 15).
Balmoral Boarding Kennels in Bambers Lane raised the alarm after one of its customers was forced to take two dogs to the vets after eating the toxic substance.
The dogs were reportedly given medication to induce vomiting and are expected to make a full recovery.
The discovery of the palm oil has been reported to Fylde Council and led to a warning being issued yesterday afternoon.
A spokesman for Fylde Council said: "We have had a report of some palm oil washed up on the beach on Wednesday morning.
"Please keep a close eye on children and keep dogs on leads for the next few days whilst we continue to monitor the situation."
The white lumps have also been found washed up on other beaches along the North West coast, with the National Trust confirming recent reports that a dog has died after eating palm oil in Formby, Merseyside.
According to Vets Now, palm oil is not poisonous to dogs, but it does have a laxative effect and, if eaten, can cause sickness, diarrhoea, dehydration and, in extreme cases, pancreatitis.
It can also cause blockages in the gut due to its semi-solid state and there have been a number of reports of dogs becoming seriously ill after ingesting palm oil.
Vets Now said palm oil can also be dangerous to dogs because it can contain other toxic products mixed in it, such as diesel oil from ships.