Is any substance strictly forbidden for astronauts in space, because it may dehydrate, cause intestinal problems or other ailments/threats to systems if improperly handled? Anything someone may ingest is valid for an answer- drinks included. (Asking because @uhoh linked to articles about chili peppers in space (comments 1, 2).)

Imagine if something like that dispersed into the water system by accident!

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    $\begingroup$ Chris Hadfield has a video that touches on why they use tortillas instead of sliced bread. (Spoiler: crumbs are dangerous in null-G. They might get in people's eyes.) Not sure if it's expressly forbidden, or if the people who plan meals are just conscientious about it, though. $\endgroup$ – Ghedipunk Jul 19 '19 at 22:13
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    $\begingroup$ @ghedipunk Haha I probably could say the same about chili powder in 0 g. It would suck to essentially have pepper spray circulating around. Do you have a link to thay video $\endgroup$ – Magic Octopus Urn Jul 19 '19 at 22:15
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    $\begingroup$ I imagine NASA wouldn't be too happy with illegal 'foods' like psychedelic mushrooms either. $\endgroup$ – Dragongeek Jul 20 '19 at 9:40
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    $\begingroup$ @Uwe Ice cream (proper ice cream, too) has been sent to the ISS. I don't have the reference to hand right now, but IIRC it was because there was a refrigerated (or maybe just cold and well-insulated) container being sent up and there was space left. Rather than let it go to waste, it was packed with ice cream. Presumably the improved crew morale (and any other considerations - maybe it stopped the content of the chilled container shifting around during flight?) was considered more valuable than the extra cost from the increased payload weight. $\endgroup$ – Richard Ward Jul 22 '19 at 12:34
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    $\begingroup$ Pork and beans were probably forbidden by other crew members!! $\endgroup$ – RonJohn Jul 22 '19 at 16:18

At least in the Shuttle program, I'm afraid the list of forbidden foods was almost infinitely long. Anything not officially tested and approved was forbidden.

From the Space Shuttle Food System Summary (only covers the first 25 flights) here's the menu you got to choose from. Don't worry, it's only a couple of weeks at most.

enter image description here

From eating this stuff in simulations, I can attest that it's all at least bearable, although I was never quite brave enough to tackle the dehydrated Broccoli au Gratin.

enter image description here These are the beverages allowed in the first 25 Space Shuttle flights.

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    $\begingroup$ ”Shrimp Cocktail was one of the better items" did they serve astronaut food at KSP cafeteria? ;-). (Half joking, half curious as a cat) $\endgroup$ – Diego Sánchez Jul 20 '19 at 19:34
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    $\begingroup$ @sean. Oh, crap! I meant KSC cafeteria. Good catch, thanks. (And yes, literally typing while mechjeb took care of a launch) $\endgroup$ – Diego Sánchez Jul 20 '19 at 23:38
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    $\begingroup$ Cornflakes are marked as rehydratable, and milk isn't on the list. Does that mean you would inject water into a bag of cornflakes? $\endgroup$ – Robyn Jul 22 '19 at 7:42
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    $\begingroup$ @Robyn they were packaged with dried milk, so yes. $\endgroup$ – Organic Marble Jul 22 '19 at 12:11
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    $\begingroup$ I had to look up "Apple Cider" (Apple cider is the name used in the United States and parts of Canada for an unfiltered, unsweetened, non-alcoholic beverage made from apples.) because in France this is an alcoholic beverage which would have been surprising. $\endgroup$ – WoJ Jul 22 '19 at 14:14

There are in fact many foods astronauts are not allowed to eat. I'll be specifically talking about the ISS as they are the only ones currently in space.

Bread: Astronauts are not allowed to eat bread because their crumbs can go into machine and equipment, and into astronauts' eyes.

Alcohol: Russians were allowed to drink small quantities of alcohol (such as on the Mir) but NASA has prohibited this on the ISS; for obvious reasons. You don't want a drunk person in a confined pressurized vehicle 400 km above the Earth. Also because alcohol affects muscle protein synthesis (and muscles get even weaker in micro gravity) and similar to soda, many alcoholic beverages are carbonated and can cause discomfort and eructation (burps).

Salt and Pepper: Again similar to bread, salt and pepper can go into their eyes and damage equipment. Salt and Pepper are served on the ISS by being dissolved into liquids. However salt and pepper in their raw form are not allowed on the ISS.

Soda: Here on earth, the Carbon Dioxide bubbles will just pop and turn into gas, however in micro gravity, the bubbles remain in the liquid and this can cause digestive tract problems such as discomfort and fetid burps.

Food on the ISS has to follow these six categories:

  1. Compact
  2. Lightweight
  3. Nutritious,
  4. Tasty (although their sense of taste is reduced in micro gravity)
  5. Sticky or wet (to avoid crumbs or loose parts getting into equipment)
  6. Processed and pasteurized because food has to remain edible for the length of the entire mission

Because of this, many perishable foods and drinks such as fresh milk and hydrated vegetables are not allowed on space missions. If a food can follow these 6 categories, it is allowed in space (ISS specifically). If it doesn't follow even one of these categories, then it's not allowed in space.


  1. https://www.verywellfit.com/alcohol-vs-fitness-results-3121357
  2. https://www.fi.edu/5-foods-astronauts-cant-eat-in-space
  3. http://www.asc-csa.gc.ca/eng/astronauts/living-in-space/eating-in-space.asp
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    $\begingroup$ Russians are allowed to drink small quantities of alcohol -- any sources? $\endgroup$ – horsh Jul 19 '19 at 22:37
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    $\begingroup$ "Russians are allowed to drink small quantities of alcohol"? There is problem. Never Russian drink small quantity alcohol. $\endgroup$ – Quora Feans Jul 20 '19 at 8:20
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    $\begingroup$ From what I've read, Russian pre-ISS alcohol consumption in space was frequently in more than "small quantities"... $\endgroup$ – Vikki Jul 20 '19 at 21:16
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    $\begingroup$ @MichaelHarvey Over Soviet Russia, alcohol drinks you! Or did the space stations qualify as sovereign territory? I've never been quite up on all those rules and rgulations. $\endgroup$ – Cort Ammon Jul 21 '19 at 17:37
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    $\begingroup$ On the matter of bread - Heston Blumenthal included a bacon sandwich with some other food that astronaut Tim Peake was allowed to take as his "special personal food allowance" - news article - but NASA took quite a bit of convincing on this and a couple of other items... $\endgroup$ – HorusKol Jul 22 '19 at 7:49

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