I can't find any evidence of a poison taster actually dying from poisoned food or drink. There are a number of Roman tasters, or praegustators, who are known by name because their title was written on a tombstone, or through other records. Cause of death generally wasn't poison though. Praegustator was sometimes a high-ranking office under the Roman Emperors, similar to a cursus honorum, and although slaves might be employed to actually taste suspicious food or drink, the Praegustator was responsible -- on pain of death naturally -- for the Emperor's health. Some praegustators were patrician members of the imperial household, and some were imperial household slaves. I imagine the choice came down to who the emperor or aristocrat in question thought they could trust.

I think there are some modern misconceptions about the role of a food taster. There are plenty of fast-acting poisons that would show rapid symptoms -- potassium cyanide, hemlock, belladonna etc. But the ancient Romans, Greeks, Egyptians, Chinese, etc. were fully aware of dozens of other slower-acting poisons that a poison taster would never be able to detect in time to save the intended target -- arsenic being the king of these. Pliny the Elder described over 7000 known poisons, so the idea that such an unsophisticated method of detection would protect anyone from poisoning would have seemed as silly to the ancients as it does to us. Poison tasters were not intended to act as a "canary in a coal mine": their role was more involved and complicated.

Just focusing on the Romans for a moment, food tasters appear to have been employed for several reasons:

a) Fashion. Marc Antony was so afraid of being poisoned by Cleopatra that he employed a praegustator, and this then became fashionable in imperial households.

b) Deterrent. The praegustator was also a kind of chef, responsible for food creation, and required to eat whatever the Emperor ate. Their own life was therefore on the line in making sure that the Emperor's food remained uncontaminated. Kind of a strong deterrent against doing a bad job. Also, deterrent 2, would-be poisoners would know that their efforts would have to penetrate this layer of security, with increased chance of detection, and that might prevent their attempt.

c) Evidence. People, even Emperors, often became sick for mysterious reasons. If both the Emperor and his praegustator died at the same time, with the same symptoms, after eating the same food, you would have legal and logical proof that poison was used. On the other hand, if the Emperor was obviously poisoned but the taster was feeling just fine, then they would be at the top of the line of suspects. Halotus, taster for Emperor Claudius, was widely suspected in the poisoning of Claudius. If in fact he was involved, he apparently enjoyed the protection of powerful people who stood to benefit from the death of Claudius, namely Agrippina and the successor to the throne, Nero.

d) Training. If your official job title is "poison taster," and your life is on the line every time you prepare a meal, then you're naturally going to study up on the known poisons and how they can be detected in food or drink. Many poisons have a characteristic smell, taste, or chemical reaction, some of which were known in the ancient world.

e) Canary. There is some evidence that tasters, especially slaves, could indeed be used as living poison detectors, although that wasn't their primary function.

EDIT 2: removed a section violating the "current events" rule. Included below as a comment.

For some reason, people seem to want to fill this thread with things they've heard, movie anecdotes, and statistics on the speed of various poisons. None of these things actually answers the question, which involves whether a food taster ever actually consumed poison and died. If you cannot answer the question, please refrain from posting.

Thank you.

The only resource I know of on the topic (though I have to assume that there are more) is Terence Scully's "The Art of Cookery in the Middle Ages." Scully is a professor at the Wilfred Laurier University in Ontario, Canada.

He writes the following:

Everything that was intended for the prince's mouth became subject normally to two general sorts of tests, called assays: on the one hand, a test by means of a unicorn horn, and on the other, a test by what vulgarly we might today call guinea-pig experimentation. This second sort of test needs no long explanation: it derived from the principle that one should oneself be willing to stand the salubrity of what one offers to others while making the claim that it is perfectly harmless….Clearly the test assumed that any poison effective enough to do in the prince -- merely harming him could very readily prove in short order to be fatal to the poisoner instead! -- would become manifest quickly and plainly enough to spare the prince the danger of ingesting it."

The first variety of assay, that which involved the use of a unicorn horn, was more curious, perhaps because the way it operated was somewhat less obvious than the guinea-pig variety of test….The Greek physician and imaginative historian, Ctesia of Cnidus, as the end of the 5th Century BC, wrote, concerning a contemporary practice in India, that 'Those who drink from these horns (of unicorn), made into drinking vessels, are not subject, they say, either to convulsions or to the falling sickness (epilepsy). Indeed, they are immune even to poisons if, either before or after swallowing such, they drink water, wine, or anything from these beakers.'

Regular assays of both sorts, by contact with the unicorn horn and by the ingesting of test samples, were conducted extensively at several stages before anything edible was set down in front of the prince. Even before the prince came to the table, the Linen-Keeper and Hall Porter had to do an assay for poison on the tablecloths by passing the unicorn horn over them. Both the tapestry which the Hall Usher unrolled onto the prince's bench and the cushion on which he was to sit were similarly tested. The most important element awaiting the prince on his table was the salt… Conducted into the hall by the Hall Usher, the Pantler directed the Hall Porter, who then followed him, where to set the large salt dish; there the Pantler removed the lid from the salt dish and with the lid -- in order not to contaminate the salt -- picked up a sample which he passed to the Porter to taste. If the results of the test were satisfactory -- and one can only assume this meant that the Hall Porter remained hale and hearty -- the Pantler took a knife and with it transferred some of the salt from the large salt vessel into the prince's personal salt boat; the Pantler himself made an assay of this salt in the boat, and set it at the prince's place, together with other items also borne in by the Porter…"

This does not address your questions directly, but perhaps it fills in some of the context on romanticism of food tasting. Common pre-industrial-revolution poisons in Europe included Belladona and Hemlock, both alkaloids. I really don't know the speed at which these killed a person, but a small number of ca. 1900 articles I dug up suggest it's a timeline of a few hours when ingested in sufficient quantities.

Speaking speculatively, I would think the incidence of naturally occurring food poisoning far outstripped intentional attempts at murder. This, I hope, shouldn't require a source, as we all know the effects of bacteria and mold on food when it's not refrigerated or stored properly. If this is a fair assumption, then it would seem that a food taster could also be useful in sparing the nobleperson the displeasure of consuming sour milk or rotten meat.

Edited to show quote properly

Follow up: How qualified were food tasters? Were they trained to taste poisons (specifically or otherwise) within an instant, even if it wouldn't have an effect for a while, as opposed to just being a guinea pig? Or was this a very low level/low standard job?

In December of 1979, The Soviet Union was attempting to kill the sitting "Prime Minister" of Afghanistan, Nur Muhammad Taraki. The reasons that they wanted to kill him are complex and aren't really necessary to discuss here, but yeah, they wanted him dead.

Two of the attempts to assassinate Taraki revolved around poisoned food. In the first attempt, Taraki's nephew and secret police chief were poisoned (but survived). I know that he isn't quite a 'food taster' but the chief of the secret police kind of fits the mold as someone responsible for protecting the head of state, including from dangers lurking in his dinner.

A few days later, as Soviet troops were massing for the invasion, the KGB once again tried to poison Taraki. This time they managed to significantly sicken him (but not kill him-- it was a hail of bullets that eventually got him) but the attempt also severely sickened everyone that Taraki was dining with, including but not limited to his security team.

Souce is Peter Tomsen's The Wars of Afghanistan

So this isn't quite an example of a food taster being poisoned and dying on the spot, no, but it is an example of a security team consuming poisoned food and falling severely ill not once, but twice.