Question: Why is marijuana sacred among some Hindus such as [Naga Sadhu](https://en.wikipedia.org/wiki/Dashanami_Sampradaya#Naga_Sadhus)?

Shiva plays a role in this but does marijuana aid in obtaining moksha or does it have any spiritual benefits?

Answer: 
Marijuana or any other drug is not considered sacred by Hindus. There might be some exceptions where people justify it. The usual argument these people give in favour of drugs is a misleading argument that *Shiva* consumed *Bhaang*. Hence, it is okay for them to do so too. This argument has no base in it:

> 
> Q. Gurudev, we sing devotional songs in praise of Lord Shiva and Lord
>  Krishna. But back home, the people there consume Bhaang (a type of
>  Indian narcotic incorrectly thought to please Lord Shiva) while they
>  sing praises of Lord Shiva. How should one understand all this?
> 
> 
> Sri Sri Ravi Shankar: See, if *Lord Shiva* consumed *Bhaang*, then he
>  also consumed the poison that came from churning the cosmic ocean. So
>  should we also drink poison first, and then see if we stay alive to
>  drink *Bhaang*? Do not misunderstand all these things.
>  *Lord Shiva* never consumed *Bhaang*. The essential point to understand is that the *Shiva Tattva* (the most fundamental
>  all-pervading element in creation) resides in each and every one. An
>  intoxicant like *Bhaang* too cannot do anything to *Lord Shiva*’s
>  bliss, because he is above and beyond all such trivial influences. But
>  chanting his name can have a positive influence on us and elevate us.
> 
> 
> 

Excerpts from a Q&A: <http://celebrating-silence-of-life.blogspot.in/2015/08/why-good-people-suffer.html>
Yes. Marijuana is mentioned in the Vedas:

> 
> पञ्च राज्यानि वीरुधां सोमश्रेष्ठानि ब्रूमः। दर्भो **भङ्गो** यवः सह ते नो मुञ्चन्त्व् अंहसः॥ (Atharva Veda 11.8.15)
> 
> 
> 

Hindi meaning

> 
> “Patra, kand, phalphul aur mulatmak panch rajyoun se yukta aushdhiyon main Somlata sarvasherstha hai. Darbha, **Bhang**, Jau aur Dhan ye sabhi humse stut hokar **hamare dushkarmo ko katne main samarth hon.**”
> 
> 
> 

It means marijuana will destroy our bad karma