Novocain (procaine) vs. laughing gas, which one is safer?

Totally different: Novocaine is and injectable local anesthetic. Nitrous oxide is a gas that is an analgesic that can reduce anxiety. It does not anesthetize! both have good safety records. Nitrous oxide can cause nausea and vomiting if used for a long time or in high concentrations. Local anesthetic can cause palpitations, mostly due to the Epinephrine component, in some people. Rarely are people allergic to local.

Thanks for asking!: They have different side effect profile, but usually the local anesthetic-novocain would have more benign effects.