Ragwort weed (buachachalin) is poisonous to livestock and needs to be handled with care, according to Galway East TD and Minister for Rural Affairs Seán Canney.
Minister Canney issued his warning after the recent humid weather led to a proliferation of ragwort/ buachalains along roadsides.
He says farmers have to be particularly vigilant because ragwort can kill cattle and horses if it is ingested.
It is also toxic for people and can cause allergic reactions if it is absorbed through the skin.
The public is advised to wear protective waterproof gardening gloves when handling ragwort plants and arms and legs should be covered. Face masks should also be worn to avoid inhaling the weed's pollen which can cause hay fever.
Ragwort can be recognised by its small yellow flowers. Plants that are pulled should be destroyed or put into landfill.
Minister Canney says local authorities and Transport Infrastructure Ireland are responsible for the removal of weeds from main roads and motorways, but farmers also have the responsibility to ensure their lands are ragwort free .