अहो वेदध्वनिः!

(नेपथ्ये सस्वरम्) मूषको वै प्रजापतिरासीत् । तस्य द्वौ दन्तावास्ताम् । दन्तेन दन्तेन बिलं करोति, भाण्डं स्फोटयति, हविष्यान्भक्षयति । यजमानः प्रहरति; चूचूशब्दं करोति । यजमानं स्वर्गं लोकं गमयति । य एवं वेद ...

प्रजापतिदेवः − (सादरं समाकर्ण्य) अहो! वेदध्वनिः!

“(Offstage, with Vedic accent) Prajāpati assuredly was [once] a mouse. He had two teeth. Tooth by tooth he makes a hole, breaks the pot, devours the sacrificial offerings. The sacrificer strikes, he squeaks ‘choo-choo’. He conveys the sacrificer to the heavenly world. He who knows this…

Prajāpatideva: (listening respectfully) Ah, the sound of the Veda!”

From the Palāṇḍumaṇḍanaprahasana of Harijīvanamiśra (Palandumandana Prahasana of Harijivana Misra. Text Critically edited by Dr. V. Raghavan with Critical Introduction & English Translation. Golden Jubilee Publication. The Kuppuswami Sastri Research Institute. Madras–600 004. 1996), a farce about eating habits and dietary restrictions, particularly onions (palāṇḍu) and garlic (laśuna).

Here are a few additional references documenting this trepidation inspired by onions and garlic.

Manu bans them (5.5 laśunaṃ gṛñjanaṃ caiva palāṇḍuṃ kavakāni ca | abhakṣyāṇi dvijātīnām amedhyaprabhavāni ca ||) Bhojadeva’s Śṛṅgāraprakāśa 9.26 (... dravyāṇi ayajñīyāni palāṇḍvādīni...) mentions them as unsuitable for sacrificial use, at Atharvavedapariśiṣṭa 36.7 they are used in black magic. In the Tantrālokaviveka ad 29.17 (the Kulayāga chapter) they occur in a list of 12 substances used in Kaula ritual: reto harāmbu puṣpaṃ ca kṣāraṃ nālājyakaṃ tathā | pauruṣaṃ kṣmābhavaṃ chāgaṃ mīnajaṃ śākunīyakam | palāṇḍuṃ laśunaṃ caiva dravyadvādaśakaṃ śubham ||.

Update 24th of March, 2006: Some further references to garlic and onions.

Tantrasadbhāvatantra 21.172:
vaṭakaiḥ pūrakair dhūpair āmamāṃsamanvitaiḥ /
naivedyaṃ dāpayet prājñaḥ palāṇḍuṃ laśunaṃ tathā //

Devīpaṇcaśatikā (Kālikākulapañcāśatikā) 3.80ab:
palāṇḍuṃ laśunaṃ caiva maṇḍūkān kṛśarāṃs tathā /

Somaśambhupaddhati 1.9.18 (bhojanavidhi):
katakaṃ madhuśigrū ca palāṇḍuṃ laśunāmiṣe /
gṛñjanaṃ hastadattaṃ ca lavaṇaṃ parivarjayet //

Vaikhānasagṛhyasūtra 27, Khaṇḍa 21: Sentence: 6 prasūte 'ntardaśāhe gokṣīraṃ sadaikaśaphoṣṭrastrīṇāṃ payaśca palāṇḍukavakalaśunagṛñjanaviḍjamanuktaṃ matsyamāṃsaṃ ca varjanīyam \7\

Brahmapurāṇa 220.174: halabhṛtyaṃ sarṣapaṃ ca palāṇḍuṃ laśunaṃ tyajet /
mānakandaṃ viṣakandaṃ vajrakandaṃ gadāsthikam //

Garuḍapurāṇa 1.96.72: palāṇḍulaśunādīni jagddhvā cāndrāyaṇaṃ caret /
śrāddhe devānpitṝnprārcya khādanmāṃsaṃ na doṣabhāk //

Kūrmapurāṇa 2,17.19: vṛntākaṃ nālikāśākaṃ kusumbhāśmantakaṃ tathā /
palāṇḍuṃ laśunaṃ śuktaṃ niryāsaṃ caiva varjayet //

Haribhaktivilāsa 8.158–159 (attrib. to Kūrmapurāṇa): athābhakṣyāṇi
kaurme
vṛntākaṃ jālikā-śākaṃ kusumbhāśmantakaṃ tathā |
palāṇḍuṃ laśunaṃ śuklam niryāsaṃ caiva varjayet //
gṛñjanaṃ kiṃśukaṃ caiva kukuṇḍaṃ ca tathaiva ca |
uḍumbaram alābuṃ ca jagdhvā patati vai dvijaḥ //

Śikṣāsamuccaya (line 1254):
māṃsāni ca palāṇḍūṃś* ca madyāni vividhāni ca |
gṛñjanaṃ* laśunaṃ* ca * eva yogī nityaṃ* vivarjayet ||

The early Buddhist Amoghapāśakalparāja: f.2v6: madyamāṃsapalāṇḍugṛñjanakālaśunasaṅkara*kṛtaṃ(?) *cocchiṣṭaṃ (em. T; cecchiṣṭaṃ MS) viśeṣārthinā *hy ete (em. T; hyaite MS) varjyāḥ.