Avocado seeds are not considered highly poisonous to humans, but they are not recommended for consumption. The seeds contain small amounts of a compound called persin, which can be toxic in large quantities. However, the amount of persin in the seed is generally not enough to cause harm if ingested in small amounts.
That said, avocado seeds are very hard and can pose a choking hazard. Additionally, they are not easily digestible and may cause gastrointestinal discomfort if consumed. Some people grind the seeds into a powder and use them in smoothies or other recipes, but this practice is not widely recommended due to the potential risks.
In summary, while avocado seeds are not highly toxic, it is best to avoid eating them to prevent any potential health issues.