<jats:title>Abstract</jats:title><jats:p>Presence of a non‐acidic, growth‐promoting indole compound, identical in R<jats:sub>f</jats:sub> and colour reaction and closely similar in UV spectrum to synthetic indoleacetaldehyde (IAAId) has been demonstrated in extracts of etiolated shoots of <jats:italic>Pisum</jats:italic> and <jats:italic>Helianthus</jats:italic>. On chemical as well as enzymic oxidation of this neutral extract, activity passes over into the acidic fraction. This neutral substance is believed to be IAAId and occurs in the free state as short‐term, low temperature extractions indicate. On the basis of R<jats:sub>f</jats:sub>, colour reaction and UV spectrum, tryptophol has also been identified in <jats:italic>Helianthus</jats:italic> extracts. Its identification in pea extracts, however, rests only on R<jats:sub>f</jats:sub>, colour reaction and inactivity in Avena bioassays.