[Trumpisourlastchance]

Suffocation can cause foam. White Helmets also are known to apply shaving cream to corpses.

[UCANSEE2]

I thought that the real indicator of truth was in the video where the children who were foaming at the mouth and convulsing stood up at the end and were applauded.

[agere_contra]

The symptoms of pulmonary oedema caused by e.g. gassing might include the coughing up of blood or of bloody foam.

Was the foam pure white?