was recently asked this question, and realized that it’s something not too many people know about. The plain answer is yes, Cycads are poisonous, but as with most things plant related, when you dig below the surface you’ll find some interesting things.
Most parts of Cycads contain toxins that can, when eaten in large enough doses, cause sickness and even death. But the ironic thing is that the Afrikaans name for a Cycad is a broodboom (lit. Bread Tree). This comes from the fact that in South Africa and in many cultures around the world, the seeds of Cycads have been used to make flour.
In South Africa, legend has it that a group of Boer soldiers were hiding out in the hills – after a while they got hungry and decided to try cooking and eating the seeds – for the next few days they were laid out in pain, before recovering sufficiently to keep going.
In Australia, an aboriginal tribe would prepare the seeds by putting them in water to leach out the toxin, this would take about four days. The seeds were considered safe to eat once fish had started to nibble on it. At which point, the seeds were then ground down into flour and made into bread. (don’t try this at home – and if you do, don’t invite me)
But don’t go out and uproot your Cycads in a hurry. If you consider how many gardens have Cycads growing in them, and yet cases of poisoning are extremely rare.
Just as a side note – Cycads are a rather large group of plants. In South Africa, the Encephalartos (usually spiny) and Stangeria (stemless) are indigenous, while the Cycas – commonly known as Sago Palm (softer leaves with relatively small spines at the base) is not. Indigenous Cycads are a protected plant in South Africa.