Jan Baptist van Helmont[b] (/ˈhɛlmɒnt/ HEL-mont,[2] Dutch: [ˈjɑm bɑpˈtɪst fɑn ˈɦɛlmɔnt]; 12 January 1580[a] – 30 December 1644) was a chemist, physiologist, and physician from Brussels.

On the other hand, he engaged in the new learning based on experimentation that was producing men like Santorio Santori, William Harvey, Galileo Galilei and Francis Bacon.

[5] Van Helmont is regarded as the founder of pneumatic chemistry,[3] as he was the first to understand that there are gases distinct in kind from atmospheric air and furthermore invented the word "gas".

In Oriatrike or Physick Refined (1662, an English translation of Ortus medicinae), van Helmont considered earlier ideas on the subject, such as food being digested through the body's internal heat.

[11] Helmont's experiment on a willow tree has been considered among the earliest quantitative studies on plant nutrition and growth and as a milestone in the history of biology.

[12][13][14][15] Van Helmont described a recipe for the spontaneous generation of mice (a piece of dirty cloth plus wheat for 21 days) and scorpions (basil, placed between two bricks and left in sunlight).

[16] Although a faithful Catholic, he incurred the suspicion of the Church by his tract De magnetica vulnerum curatione (1621), against Jean Roberti, since he could not explain the effects of his 'miraculous cream'.

[9][18] Ortus medicinae was based on, but not restricted to, the material of Dageraad ofte Nieuwe Opkomst der Geneeskunst ("Daybreak, or the New Rise of Medicine"), which was published in 1644 in Van Helmont's native Dutch.

[22] Though Van Helmont was skeptical of specific mystical theories and practices, he refused to discount magical forces as explanations for certain natural phenomena.

[24] In 2003, the historian Lisa Jardine proposed that a portrait held in the collections of the Natural History Museum, London, traditionally identified as John Ray, might represent Robert Hooke.

In 1875, he was honoured by Belgian botanist Alfred Cogniaux (1841–1916), who named a genus of flowering plants from South America, Helmontia (from the Cucurbitaceae family).