Immortelle is often used an a diuretic. -- Divas Botanicals

A diuretic is a "substance or drug that tends to increase the discharge of urine." -- dictionary.com

"Immortelle has had many medicinal uses. Having been the chosen remedy for chronic ailments of the skin and lymphatic system. It has also been extensively used in Europe for respiratory complaints such as asthma, chronic bronchitis and whooping cough." -- Alexander Essentials

*** So it's probably added to cigarettes in order to ease the smoker's throat. ***

 

im·mor·telle   Audio pronunciation of "immortelle" ( P )  Pronunciation Key  (môr-tl)
n.
Any of various plants, such as species of the genera Helichrysum, Xeranthemum, and Erythrina, having flowers that retain their shape and color when dried.

[French, from feminine of immortel, immortal, from Old French. See immortal.]
Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
 

immortelle

\Im`mor*telle"\, n.; pl. Immortelles. [F. See Immortal.] (Bot.) A plant with a conspicuous, dry, unwithering involucre, as the species of Antennaria, Helichrysum, Gomphrena, etc. See Everlasting.

Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.

immortelle

n : mostly widely cultivated species of everlasting flowers having usually purple flowers; southern Europe to Iran; naturalized elsewhere [syn: Xeranthemum annuum]

Source: WordNet ® 1.6, © 1997 Princeton University