is it safe to simultaneously use cannabis and ayahuasca?

It is never safe to take a psychedelic drug.

Cannabis is also psychedelic, even though it gets downplayed a looot. It is less psychedelic than other things, as it doesnt interact with your Serotonin receptors (which I would call "hooking in your core sense of wake consciousness"). But still.

Now DMT works differently. And may be harder on you.

Cannabis is not a good drug to relax if you are on a psychedelic. Your sober mind may find the effects relaxing, but it is still a drug that acts on your brain, and it is less "ideal" than your sober state, it is stress on the brain.

So if you are on a comedown or at the peak and can estimate the effect, you may be able to mix it. But please dont mix at the start.

You have one drug stressing your brain, and add another drug that probably doesnt overlap much but stresses other parts.

And of course, please respect set and setting, have a sober buddy with you that you 100% trust. Have water, space to walk, scream, cry, whatever.

People underestimate how much space they may need.

The effects potentiate each other, so you will be tripping much harder.

If you tolerate weed well otherwise, it can work out well. If you’re prone to paranoia, anxiety, and similar effects, this combination can great increase them.