Convolvulus prostratus (commonly known as Shankhpushpi) has a long history of use in Ayurvedic and Unani medicine as a brain tonic and nervine. Traditional texts describe its use for calming the mind, enhancing memory, and reducing symptoms of nervousness and anxiety, which are effects often associated with support of the parasympathetic nervous system (PNS). The PNS is responsible for rest-and-digest activities, so herbs that promote relaxation and reduce stress are sometimes considered supportive of this system.

Several preclinical studies have investigated the anxiolytic, sedative, and cognitive-enhancing properties of Convolvulus prostratus extracts in animal models. These studies suggest possible mechanisms such as modulation of neurotransmitters like GABA and acetylcholine, which could theoretically influence parasympathetic activity. However, robust clinical evidence in humans specifically demonstrating direct support of the parasympathetic nervous system is lacking. Most available data rely on traditional usage patterns and animal research rather than high-quality clinical trials.

In summary, the use of Convolvulus prostratus to support the parasympathetic nervous system is justified primarily by traditional evidence, with some low to moderate support from preclinical studies, but lacking in direct scientific validation in humans.