English Ivy (Hedera helix) has a long history of traditional use for respiratory ailments, but in recent years, its extracts—particularly standardized saponins—have been scientifically investigated for their effects on the respiratory tract. Ivy leaf extract is recognized in several European countries as a phytomedicine for the symptomatic treatment of chronic inflammatory bronchial conditions and productive coughs. The mechanism is thought to involve its saponins, which may increase secretion of watery mucus and have mild bronchodilatory and anti-inflammatory effects.

Regarding pneumonia specifically, the evidence is limited. Most clinical studies and reviews focus on its use in acute or chronic bronchitis, not pneumonia. Some small-scale studies and open-label trials have reported improvements in cough and expectoration in patients with lower respiratory tract infections, sometimes including pneumonia, but these studies are often underpowered, lack placebo controls, or mix patient populations. There is no robust, high-quality clinical trial data demonstrating that English Ivy effectively treats pneumonia, reduces its severity, or prevents complications.

In summary, while there is scientific interest and some clinical evidence supporting Ivy leaf extract for general respiratory symptoms—mainly cough and mucus clearance—there is insufficient direct evidence to support its use as a treatment for pneumonia itself. Its use in this context is mainly as an adjunct to conventional therapy for symptomatic relief, not as a primary or standalone treatment.