Direct answer: In most cases, marijuana can be detected in saliva for up to about 24 hours after last use, though for some people or with heavier use, it can extend to 2–3 days or slightly longer. The exact window depends on factors like how often a person uses cannabis, how much was used, individual metabolism, and the sensitivity of the saliva test. Key factors that influence detection in saliva:

• Frequency of use: occasional users tend to clear THC faster than regular or daily users.
• Amount and potency: higher doses can stay detectable longer.
• Metabolism and oral chemistry: faster metabolism or certain oral pH conditions may shorten the window.
• Test sensitivity: some tests are more ultra-sensitive and may pick up lower THC levels.

Practical notes:

• Saliva tests are typically favored for their short detection window compared to urine or hair tests, making them more suitable for roadside or on-the-spot screening.
• Hydration and oral hygiene have a minor effect; they’re not reliable methods to “beat” the test.

If you need this for a specific jurisdiction or testing scenario (e.g., roadside testing, workplace policy, or legal considerations), I can tailor the information to that context and provide typical cutoffs or guidelines referenced by official sources.