Where the alkaloids are made
The opium poppy produces its alkaloids in a milky latex that runs through the plant and is most abundant in the wall of the unripe capsule. That latex contains morphine as the main alkaloid, together with codeine, thebaine, papaverine and noscapine. Raw opium, which is dried latex, contains roughly 8 to 14 percent morphine by dry weight.
The seeds ripen inside that capsule. They are not part of the latex system, and clean seed taken straight from a ripe pod contains very little alkaloid.
How the alkaloids reach the seed
Germany's Federal Institute for Risk Assessment (BfR) and the Bavarian food authority (LGL) describe the same mechanism. During mechanical harvesting, seeds come into contact with the alkaloid-containing latex of the capsules, and fragments of capsule end up mixed with the seed. The alkaloids stick to the outside of the seed, in the pits of its surface, and travel with it into trade.
The BfR named three factors that drive the amount:
- Variety. Some varieties are bred for seed, others for alkaloid production. Pharmaceutical varieties carry far more.
- Harvest time. The BfR lists the moment of harvest as a factor, without putting a number on it.
- Origin and method. Growing region and harvesting technique differ between countries and farms; the BfR discussed newer harvesting machines that crush the capsules as a possible cause of the rising levels it saw at the time.
How much morphine is on poppy seeds
The amount varies a great deal, which is the core of every problem on this site.
| Measurement | Morphine | Source |
|---|---|---|
| EU legal maximum for consumer seed (morphine + 0.2 x codeine) | 20 mg/kg | Regulation (EU) 2023/915 |
| BfR provisional guide value, 2006 | 4 mg/kg | BfR press release 05/2006 |
| One batch of seed tested in a US study, 2015 | about 220 mg/kg (plus about 39 mg/kg codeine) | Samano et al., J Anal Toxicol |
The seed in the 2015 study came from a single source and carried roughly ten times the EU maximum. That is one batch, not an average, and it shows how far untreated seed can deviate. The EU limits page explains how the European rules work.
What cleaning and baking change
Because the alkaloids sit on the outside, industrial cleaning and heat treatment remove a large share before seed reaches shops. The European Commission puts the reduction from processing at 25 to 100 percent. The Bavarian authority notes that intensive processing breaks down the alkaloids during manufacturing.
Two consequences follow from that range:
- Seed bought as food in the EU is usually treated and tested. The Bavarian authority reported in March 2026 that poppy seed sold to consumers complied with the limit, while some batches traded between businesses for further processing still showed notable levels.
- Baked goods still contain some morphine. The same authority found morphine in most poppy seed bakery samples, with the limit reached or exceeded only in individual cases. Poppy seed rolls were generally lower than poppy seed cake or pastry swirls, which contain much more seed.
Processing lowers the content; it does not reliably bring it to zero. What remains can be enough to explain a positive drug test. For seed that meets the EU limit, normal food portions stay small; EFSA's concern lies with high intake and with seed from high-alkaloid varieties.
Other alkaloids on the seed
Morphine is not the only alkaloid. Codeine is usually present at lower levels. In 2023 the US Department of Defense warned that some poppy seed varieties may have higher codeine contamination than previously reported. Thebaine is also found; the European Food Safety Authority (EFSA) said in 2018 that dietary thebaine might pose a health risk but that data were too limited for a full assessment.
Where to go next
- Can poppy seeds make you fail a drug test
- EU limits for morphine on poppy seeds
- Why poppy seed tea is dangerous
Updated